Understanding Image File Formats

Understanding image file formats by Monica Galvan

Understanding image file formats: What should I use?

Ever curious about what the file extensions of your images mean and which are the best to use? There’s so many it’s easy to confuse them! Here are a few of the most common file names and best examples for using each. Understanding image file formats will help you in the exporting phase.

.JPEG

JPEG, short for Joint Photographic Experts Group, is the most commonly used image format. JPEG files are classified as “lossy” which means a lot of the information is lost from the original when you save as a JPEG. JPEG compresses the information to keep the image file size small so it’s understandable you would lose image quality as a result.

If you’re using a DSLR, you have the option to choose the file format you shoot in within your camera settings. I shoot in RAW to capture all image data and avoid this image compression because I want the best photo possible. However, those RAW images take up quite a bit of space on your memory cards and hard drives so be mindful of this. Each individual RAW file for me starts at around 25MB. You can also choose to shoot in both RAW and JPEG or JPEG only.

Pros

  • Capable of displaying millions of colors without dithering which is important for photographers to capture fine details

  • Most commonly used and accepted

  • Maximum compatibility

Cons

  • Image compression

  • Does not support transparency (but .PNG does!)

  • Cannot be animated (you’ll want to create a .GIF to achieve this affect)

.GIF

GIF is short for Graphics Interchange Format. This is the oldest format on the web, existing since 1989. GIFs are limited to a color palette of only 256 colors so it's not ideal for detailed photographs. Image size is generally small compared to most other types. GIFs are most suitable for simple graphics, diagrams, or logos with few colors however, PNG is often the better choice.

Pros

  • Can support transparency

  • For small, looping animations

Cons

  • Can only support 256 colors, not ideal for detailed and colorful photos

.PNG

PNG is short for Portable Network Graphics. PNG is an image file format specifically designed for the web. It’s similar to GIF but it supports millions of colors instead of only 256. PNG is great for text, line art diagrams, and simple graphics.

Pros

  • Supports transparency

  • Can support 24 bit RGB color images and grayscale

  • Lossless, meaning it doesn’t lose quality (unlike JPEG)

  • Superior to GIF

Cons

  • Does not support CMYK and is not designed for print graphics

  • File sizes can be large so it's not best for complex photographs

  • Cannot be animated

  • Not all web browsers can support PNG

.TIFF

TIFF is short for Tagged Image File Format. The format was originally created by the company Aldus for use in desktop publishing and is popular among graphic designers and professional photographers. TIFFS are lossless, the best quality, and are versatile. They are ideal for printing purposes but not for the web as the files are too large to load on the web.

Pros

  • Best quality image format since all color and data is stored nothing is lost

  • Best for printing

  • Flexible, can be lossy or lossless

Cons

  • Large file sizes

  • Long transfer time

  • Slow loading time, not ideal for web

.PSD

PSD is the Adobe Photoshop native file format. PSDs are used for editing photos within Adobe Photoshop. You can create layers with masks, transparencies, text, basically anything you can dream up in Photoshop! Purely for editing purposes so you cannot upload it onto the web as is, you would need to export it to either JPEG, PNG, or GIF.

Pros

  • Great for layering and editing within Photoshop

Cons

  • Not compatible on the web

ResourcesMonica Galvanfile formats, photography terms