WideImage supports all formats that are natively supported by the GD extension on the server (this currently includes GIF, PNG, JPG, GD, GD2, WBMP, XBM, XPM). It also supports BMP (read/write) and TGA (read only).
BMP and TGA formats support is quite stable, thanks to de77.com’s code. There are a few problems now and then, but nothing serious.
These formats are supported for saving the files: GIF, PNG, JPEG, BMP, GD and GD2.
Support for more formats is planned, but not a high priority. If you’re willing to contribute some code for loading and saving in various formats, you’re more than welcome.
WideImage supports cross-format conversion; you can easily load an image in one format, then save it in another:
Be careful when converting between formats, though: some quality and image information may be lost, and size of the resulting file may differ noticeably.