You can save to the following formats:
- GIF* — lossless LZW compression, maximum of 256 colors (stored in a palette), useful for non-photographic Web graphics
- JPEG — only True Color and grayscale color depths are supported; compression is lossy (more compression = more loss of detail); great for photos
- PNG* — a modern, universal format; has lossless ZIP compression (better than LZW); can use a palette but does not need to; does not support EXIF
- TIFF* — a classical DTP format; supports the most options of all the formats (LZW/ZIP/JPEG/RLE compression or no compression; palette or no palette; CMYK colors)
- TGA — a historical format
- BMP — the standard Windows image format; normally uncompressed; most picture software supports it
- PCX — historical format; RLE compression; only useful for simple line drawings
- JXR*, HDP – quite new formats; advanced versions of their "parent" JPEG; support 48-bit color depth
*save pictures to these formats to preserve transparency.
Progressive – the picture will be saved in such a way that it can be displayed (at reduced quality) before it is done loading. This is only useful for the Web, and only for large pictures and/or audiences with slow connections.
JPEG compression – special lossy compression developed for efficient storage of photographs. The more compression, the more damage to the picture (loss of detail). However, you can get quite good compression without visible damage. For high-quality photos use 90 and above; for previews, you can use lower values like 75. Compression damage varies depending on the nature of a picture, so if you are trying to walk the line on compression vs. quality, be sure to preview each individual picture, not just one. For more information, see Lossy JPEG Compression and Lossless Operations.
This classical DTP format supports a wide range of color depths, color models, and compression types.
RAW files store unprocessed ("raw") data from camera sensors. RAW is actually not one format, but a variety of formats with this kind of data. RAW files have greater color depth than JPEG (48 bits), they do not suffer quality loss from compression like JPEG does, and they offer you a chance to achieve better white balance, etc. than your camera can when it comes time to produce JPEGs or TIFFs. (You cannot just leave pictures in RAW, because RAW files cannot be printed/published.) On the other hand, it takes time and skill to get better outputs from RAW files than you would if you just left the work to the camera.