An Ultimate Guide To Image File Formats
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Image files are important digital file types that comprise a large percentage of personal computing and business documents used across various departments like web development, advertising, marketing, graphic design, photography, etc.
Every department has different uses for each image format. Thus it’s crucial that you get to know the different types of image file formats and what they’re used for. Images are crucial elements of graphic design that can help you engage your clients, promote social sharing and increase conversions.
Images are powerful business communication tools that can significantly increase your business growth. However, if you fail to use the correct image file formats, you could lose your client’s interest, cause errors, or slow down your website. This article will help you understand the different types of image file formats, their key features, how they work, and the best time to use them.
What is an Image file format?
An Image file format is used to save or store digital images in both 2D and 3D format. The data stored in image formats could sometimes be compressed or uncompressed. Most commonly used image formats are JPEG, PNG, and GIF.
What is Raster File Format?
Raster images are made up of grids of tiny, square dots called pixels, with each pixel assigned a color that lines up with one another to form the image. Every raster file has a defined color, position, and proportion based on resolution.
So when you resize, stretch, or enlarge the images, they become blurred, distorted, or pixelated because the software detects that image data is missing based on the surrounding pixels. This is why the higher the resolution of a raster image, the more details can be seen in a picture.
Raster images are typically larger than vector images and are best suitable for complex images with smooth edges and color gradients, like photographs, digital artwork, and graphic design projects. The most commonly used raster file types on the web include JPEG, PNG, or GIFs. Adobe Photoshop is the industry-standard image editor widely used to create, design and edit raster images and add effects, textures, and shadows to the designs.
Before we look at the different types of raster file formats, we must understand the critical differences between lossy and lossless compression and RGB and CMYK.
Lossy Vs. Lossless Compression
Depending on how the format handles image data, every raster image file can either be lossy or lossless.
Lossy compression is a process of removing or analyzing some of your image data. This process involves reducing the number of colors in your image or analyzing it for any unnecessary data to show what the original image looks like. While this process significantly reduces the image file size, it also reduces image quality.
Lossless compression, on the other hand, captures all the data of the original image file and only takes away the non-essential metadata. In this method, no data is lost from the original file, photo, or piece of art – which is where the word “lossless” comes from. Although the files are compressed, all lossless formats can reconstruct the image to its original state – which means it preserves the image quality.
RGB vs. CMYK
All raster images are saved in either one of these two primary color models: RGB or CMYK.
RGB is a light-based color model for red, green, and blue, the three primary colors that combine to create other colors. Most files saved in this format are optimized for mobile phones, the web, film, videos, or anything on a screen.
CMYK is a four-color printing model for Cyan, Magenta, Yello, and Key (another name for black). These colors represent the four inks that are combined during the printing process. Most of the files saved in this format are optimized for printing.
8 Types of Raster Image File Formats
Now that we have gone over the definition and elements of raster files, here are the eight raster image file types, their pros, and when and when not to use them.
1. JPEG Files
JPEG is a lossy raster format that stands for Joint Photographic Experts Group. It is a widely used image file format online, especially for photos, email graphics, and large web images like banner ads. As part of lossy compression, JPEGs reduces some image data to reduce its file size, ruining the image quality. Also, its small file size allows users to save more space on storage disks or memory cards.
Remember that JPEG and JPG are typically the same file formats but with different file extensions and acronyms. It is important to note that JPEGs don’t support transparency, unlike PNG and GIF formats.
Most social media platforms like Facebook and Instagram automatically convert uploaded image files to JPEGs.
- All browsers and OS support it.
- It possesses a fairly low file size.
- Its lossy image compression might lead to poor text readability
Use JPEG WHen
- You are working with online photos or artwork because its type of compression makes it easy to edit and download files quickly.
- You want to print photos or artwork because JPEGs are ideal for editing and printing at high resolution with low compression.
- You need to send a preview photo, design, or artwork to the client quickly and without taking up too much space.
Don’t use JPEG when
- You need a layered, editable image because JPEGs are flat image formats and all edits saved cannot be undone.
- You need a graphic with transparency.
2. PNG Files
PNG, an acronym for Portable Network Graphics, is a lossless raster format. Unlike JPEGS, PNG files maintain details in a picture and contracts between colors and tend to have better text readability than JPEG.
It has built-in transparency with high color depths. PNG is increasingly becoming popular for banners, screenshots, infographics, and other images and text graphics.
Also, unlike GIF formats, PNG supports more colors. PNG files can handle up to 16 million colors, while GIF files support only 256 colors. Their ability to retain quality and transparency makes them an ideal choice for logos.
- It is transparent
- It has higher-quality images and visible text.
- High-resolution PNG files can slow down your website because of their large size.
Use PNG WHen
- You need a small file size since most PNG files can be reduced to tiny sizes without losing their quality.
- You need high-quality transparent web graphics.
- You have illustrations or graphics with limited colors.
Don’t use PNG when
- You are working on a print project. Although you can still use PNG, you are better off with a JPEG (lossy) or TIFF file.
- You are working with photos or artwork. PNGS are high-resolution files that can be large and not ideal for photos on the web.
3. GIF Files
GIF is a lossless raster image format that stands for Graphics Interchange Format. It has a limited palette of 256 colors and 8 bits per pixel, which means it has less high image quality than other raster formats.
GIF is a widely used web image format for animated graphics for social media memes, banner ads, and email images.
Although GIFs are lossless, they can be exported in several customizable settings that reduce the image information and amount of colors to reduce the file size. Importantly, GIFs are supported by all major browsers and operating systems, as well as their standard image file formats.
- It supports animation or animated graphics
- It has a low file size
- It has an 8-bit limit that causes limited image quality.
Use GIF WHen
- You need transparent image file formats.
- You want to work with a small file size.
- You need to create web animation
Don’t Use GIF WHen
- You need a layered, editable image whose editing can be undone.
- You need a photographic-quality image file format.
- You need to print an image with high depth.
4. TIFF Files
TIFF, an acronym for Tagged Image File Format, is a lossless raster file format. Its high-quality feature makes it an ideal choice for storing and editing desktop publishing, photography, and graphic design that will later be used for print. You will likely encounter TIFF files when you take a photo with a professional digital camera or scan a document.
Most professional graphics applications like Adobe Photoshop and Illustrator support TIFF files that don’t use compression. Note that TIFF images tend to be large and can be used as a container for JPEG images.
- It has high-quality files that are perfect for print publishing or storage.
- It has a large file size
- It has limited browser support
Use TIFF WHen
- You need a high-quality scan for a document
- You need high-quality print graphics
Don’t Use TIFF WHen
- You are working with web graphics and need to display high-quality images online
5. PSD Files
PSD is an image format that stands for Photoshop Document. It is a proprietary original design file created in Adobe Photoshop and is fully editable with image adjustments and multiple layers. They are primarily used to create and save image documents and other graphical works on Photoshop.
It can be exported into any image file format, including JPEGs and PNGs. However, note that PSD is not a web-safe image format. Hence it is not supported by any browsers or stand image editors.
- It has lossless image quality
- All its filters, paths, transparency, and editing are fully customizable and reversible.
- It has large file sizes
Use PSD WHen
- You need to edit artwork for digital or print
- You need to retouch images and add effects
- You want to create a website or app mockup
- You want to get fancy with animation and video
- You want to create digital images or videos for the web, such as email headers, videos, banner ads, and social media images.
Don’t Use PSD WHen
- You want to print your photos or graphics.
- You want to post a photo or graphics online or send a quick preview to a client
6. RAW Image File Formats
Raw image formats are file types that contain unprocessed data captured by a digital camera or scanner’s sensors. It is one of the file formats digital cameras use to capture and store high-quality images for editing and post-production later on.
Essentially, these images are adjusted for color, exposure, white balance, saturation, etc., before they are converted and compressed into JPEG or TIFF file formats. Although there are many raw formats, some popular forms are DNG for Adobe, NEF for Nikon and CRW for Canon.
Please note that Raw image are not meant for web sharing and are not supported by any major browser or image viewer.
- It has high-quality pictures with more variability in colors.
- It has a huge image file (a raw file can be up to 20 to 40 megabytes).
Use RAW WHen
- You want to capture and edit some of the most versatile images.
Don’t Use RAW WHen
- You want to print your photos.
- RAW files are best suited for photo editing, so don’t use them when working on web graphics.
7. BMP Files
BMP which stands for Bitmap is an outdated raster image file that maps individual pixels, thereby causing little to no compression on a given image. BMP files are enormous and challenging to store or process. As they have lower quality than PNG or WebP, BMP files are less desirable for web usage.
BMP files used to be one of the most common image file formats in the past, but many image files with higher quality and lesser file sizes have overtaken them. Most browsers and operating systems support BMP files and default image viewers and editors, such as MS Paint.
- All major browsers support it, such as Chrome, Edge, Firefox, Internet Explorer, Opera, and Safari.
- It is the default image file format in most OS image editors, like MS Paint.
- It is no longer used by many web users
- It has a huge file size
8. HEIF Files
HEIF stands for High-Efficiency Image File Format. It is an image format developed by the MPEG video format team to be a direct competitor to JPEG. It is an image quality that will decrease when you enlarge it. HEIF has twice as much compression efficiency as JPEG formats. With the same file size, HEIF provides better-quality images than JPEGS.
The downside of HEIF is that it has no browser support and limited OS support. It is only supported by macOS Sierra, iOS 11, and later versions, and this doesn’t include Safari support.
- It has a great quality-to-file size ratio.
- It has limited OS support.
- It is not supported by any major browsers.
What is Vector File Format?
Vector image files are digital artworks created on mathematical equations – where the computer calculates points, lines, and curves. A path is defined by a stand and endpoint connected by lines and curves that can be square, straight lines, or curvy shapes. Each equation can be assigned a color, stroke, or thickness that can turn shapes into art.
Unlike raster images, vector images don’t depend on resolutions as much. Since they are defined mostly based on an algorithm, when you shrink, enlarge, or distort them, the shapes get larger and won’t lose details or get pixelated. The lossy or lossless compression doesn’t apply to vector images.
Importantly, vector image files have smaller file sizes than raster files. Famous examples of vector image files are SVG, EPS, and AI, mainly used for logos, icons, or fonts.
5 Types of Vector Image Formats
With a clear understanding of what vector image files are, here are five vector image file types, their pros, and when and when not to use them.
1. PDF Files
PDF stands for Portable Document Format and is an image format used to display illustrations or documents and can also be used to save images and illustrations. It works for different devices, applications, web browsers, or operating systems. Most PDF files are built on the same PostScript language as EPS, making it an excellent printing choice.
Although PDFs have a vector graphics foundation, they can display everything from raster images and graphics to spreadsheets and form fields. As a vector file with lossless compression, you can enlarge a PDF image as much as you want. It is also the universal standard file format most printers request to produce a final design.
All major browsers support PDF file format but you can’t use PDF to display images as web content. Both Adobe Photoshop and Illustrator can export straight to PDF, making it easy to get your design ready for printing.
- It allows you to include links, CTA buttons, and other interactive elements
- It has indexable and searchable text, which makes it perfect for in-depth infographics or reports.
- It is supported by major browsers
- It cannot be included in web content but has to be loaded and read as a separate file.
Use PDF when
- You want to display documents on the web
- You are ready to print your document or design
Don’t use PDFs when
- You need to edit your document or design.
2. EPS Files
EPS stands for Encapsulated PostScript and is a vector image format that is primarily used for storing illustrations in Adobe Illustrator and other illustration software like CorelDraw. EPS can include both vector and raster image data. EPS files like SVG files, are text-based documents that outline shapes and lines with code rather than map pixels and colors.
- It supports lossless scaling.
- It is a printer support for document and designs.
- It is not a standard web image file format and is not supported by any major browsers.
Use EPS when
- You must send a vector logo to a designer, client, or printer.
Don’t use EPS when
- You need to display an image online
- You are working with photographs or artwork.
3. SVG Files
SVG files stand for Scalable Vector Graphics. It is an XML based vector image format developed by W3C as a markup language for rendering two-dimensional (2D) graphics or images within a browser. Unlike raster image format, SVG files don’t rely on pixels but instead use XML text to outline lines and shapes, similar to how you create mathematical equations and graphs.
As a result of its small size, it can scale, search, index, or compress without reducing its quality, making it an ideal file format for the web. SVG files can also be edited on graphic editing programs and text editors.
- It has small file sizes and lossless calling for shapes, texts and simple illustrations.
- It is supported by all major browsers.
- It is not an ideal file format for images or complex drawings.
- Most default image editors don’t support SVG files.
Use SVG when
- You want to create a computer-generated graph and diagrams for web publishing
Don’t use SVG when
- You need a file format for printing.
4. AI Files
AI file format stands for Adobe Illustrator and is based on the EPS and PDF standards developed by Adobe. AI files can also include embedded or linked raster images despite being a vector-based format. It is not only used to save images but to create and edit graphical projects and can be scaled without losing its quality.
Note that AI files are not meant for use on the web and are not supported by browsers or default image viewers.
- It allows you to scale up or down illustration sizes freely.
- Its strokes, lines, filters, and shapers are easily customizable and reversible.
- It has large file sizes
Use AI when
- You need to create a logo, brand mascot, or icon.
- You want to set type for a logo
- You need to edit a vector design
- You want a one-page print piece
Don’t use AI when
- You need to edit images
5. INDD Files
INDD file formats is a default format for Adobe InDesign for saving project files such as styles, page content, swatches, and more to customize or edit later. Adobe Indesign is a desktop publishing software used to work on page design or layout for digital and print use, such as magazines, brochures, and newspapers.
An INDD file format can contain multiple pages, making the file size large. Note that the INDD file format is not web-safe; hence, it is not supported by significant browsers or default image viewers.
- It supports large, multi-page design projects with customizable elements
- Major web browsers do not support it
Image file formats are extensions you can save as an image, graphic, or document for various uses. Using the correct image formats can help you find the most optimized performance for your needs. When you understand the different types of image file formats, what they are used for, and when and when not to use the, you can improve your website’s loading speed and create a better experience for your users.