When you take a photograph, the camera is capturing data, which creates a digital image. But there are many different types of image file formats that can be retrieved and edited using post-processing software.
The most commonly-used formats are:
- JPEG (Joint Photographic Experts Group)
- TIFF (Tagged Image File Format)
- DNG (Digital Negative Format)
- PNG (Portable Network Graphics)
- GIF (Graphics Interchange Format)
- BMP (Bitmap Image File)
- PSD (Photoshop Document)
Choosing the right file format is important and can even be critical, depending on the level of quality – and the level of post-processing – that you require.
Now, to help you better understand the different file formats, and to ensure that you pick the right format for your needs, we’ve put together this comprehensive guide. It covers the pros and cons of using each image file format – so that, by the time you’re finished, you’ll be able to select the perfect format with ease!
JPEG is probably the best known of all image file formats, and it’s what many cameras use as the default output.
The thing you should remember is that JPEG files are compressed in-camera, and thus result in a loss of detail and quality. They are essentially set up to store as many images on the memory card as possible.
Some cameras will have options for different JPEG quality levels (e.g., low, medium, and high). The better the photo quality, the less compression the camera will perform on the original photograph.
Generally speaking, JPEGs should be used:
- When the photos are for personal use, for social media, albums, and small prints, and are not intended for large prints
- When you don’t intend to enhance or edit the photos much in post-production
- For sharing images via email
- The small file size means more images can be stored on a single memory card
- Quicker file transfer times, due to the smaller file size
- Loss of quality due to image compression
- Less opportunity for image manipulation in photo-editing software
TIFF is commonly used in the photography industry; it’s generally requested by publishers. Even if the end file format will be a JPEG, the initial file is often a TIFF.
TIFF files are usually uncompressed, so they offer the opportunity for extensive post-processing. And because TIFFs are uncompressed, they are much bigger files, and will take up a lot of space – both on your memory card and on your computer.
Some cameras offer TIFF as their highest-quality image format.
- Ability to manipulate photos extensively in editing software
- Option to print at the highest quality and at much larger sizes
- Much bigger file sizes (so more storage is needed)
- Longer transfer and loading times due to file size
Simply put, RAW is the best option if you want to get the highest-quality files from your camera, and it’s the option preferred by professional photographers. If you don’t use RAW files, then your camera will make adjustments automatically to your images, and these will be permanently embedded into your photos.
RAW files are created using a process that retains all of the information originally captured. This means that adjustments such as white balance, exposure, contrast, saturation, and sharpness can all be altered in image-editing software after the photo has been taken.
Photographing in RAW format requires plenty of memory cards, not to mention considerable post-processing time. It also requires some basic knowledge of image-editing software such as Adobe Lightroom, because files will have to be edited and converted out of the RAW format before they can be used (i.e., before they can be shared online, printed, sent to friends, etc.).
- The highest-quality image is captured
- Extensive options in post-processing
- Significant time is needed to convert and edit photos (you must edit RAW files)
- Bigger file sizes require more storage and longer post-processing times
DNG (Digital Negative)
Just about every camera these days uses a different proprietary format to capture RAW files. Even cameras from the same manufacturer will often use different formats, which means image editing software must be able to read files from all of these different cameras.
As a result, editing software providers face a challenge: how to manage and continuously provide updates for their program so it can read all these different file formats.
Enter the DNG.
This file format, created by Adobe, is an attempt to provide a standard RAW file for all manufacturers and cameras.
The DNG is offered as a main RAW file format, or as an alternative to the manufacturer’s native RAW format. One of the problems with keeping images in the original RAW format is that, several years from now, you may be unable to access these files, because they are specific to cameras and manufacturers.
But using an Adobe DNG Converter means you can also store your RAW files as DNGs for maximum future-proofing.
This does add another step to the post-processing workflow, which takes extra time. However, editing software such as Lightroom can convert large batches of files to DNGs so that it doesn’t have to be done manually.
- Ability to use image-processing software such as Lightroom and Photoshop
- Possibly the safer option long-term, because it guards against the inability to open or access files in the future
- Extra time needed to convert camera RAW files to DNGs (if your camera does not have the option to create files in this format)
Designed in the ’90s as an improvement on the GIF file format, PNG files are ideal for use on the internet.
PNGs are compressed in a lossless format, and therefore retain all detail. But unlike other file formats, PNG quality doesn’t mean big file sizes – and this is useful on the internet, because you need pages to load quickly.
The other benefit of PNG files is that they allow for partial and total transparency, which is ideal for overlays and logos.
- Lossless compression makes for good image quality, which isn’t compromised when editing
- The ability to maintain transparency, which is important for graphics such as overlays and logos
- Quality is not good enough for printing at any size
Like PNGs, GIFs are ideal for use on the internet. Lossless compression means image quality is not sacrificed, and like PNGs, GIFs offer the ability to maintain transparency (though they don’t support partial transparency). GIFs also allow for animation.
However, the limitation of GIF files is that they can only contain a maximum of 256 colors. Therefore, GIFs are not the best choice for photos, but rather for images with a limited color palette.
- The small file size makes GIF files ideal for use on the web
- Files can contain animation
- The limited colors make GIFs a poor choice for photos
- GIFs don’t support partial transparency like drop shadows
Another lossless file format, the BMP was invented by Microsoft, initially for use on the Windows platform. However, BMPs are now recognized by programs on Macs, as well.
BMPs are large files, as color data is saved in each individual pixel without any compression. As a result, BMPs provide a high-quality digital file, which is great for use in print but not ideal for the web.
- Can be used for printing, as the images are high quality
- The large file size means a lot of storage is required
This file type is what Adobe Photoshop uses as a default to save data. The big advantage of the PSD is that it allows for manipulation on specific individual layers, rather than on the main image itself.
This makes PSDs absolutely essential for any sort of extensive manipulation of the original photograph, such as retouching. PSDs give far greater flexibility and the ability to fine-tune an image, because layers can be added, removed, or edited at any time without affecting the original photo.
Once a layered PSD file is flattened (this essentially merges all of the layers), it can’t be undone. So make sure you save your file as a PSD before flattening if there’s a chance you might want to rework some of the layers later on.
- Ability to manipulate the image extensively on separate layers
- Once the image is ready, it can be re-saved as any other file format
- Layered files can be incredibly large in size due to all of the additional data they store
Image file formats: Conclusion
Now that you’ve finished this article, you know all the common image file types.
Professional photographers generally capture in RAW format (even if the final file needed is a JPEG), convert those files to DNGs, then edit in software such as Photoshop or Lightroom.
But as you can see, choosing the right file format when capturing the original photo – then choosing the right file format when saving the photo later – is absolutely essential.
What’s your favorite image file format? Do you use any formats not mentioned in this article? Share your thoughts in the comments below!