Tom's Editor Desktop is an image viewer. It can read quite a lot of C= 64 image formats, for example: Koala Painter, Drazpaint, CDU-Paint and Dolphin Ed.
Reading images from C64 was the main goal of this program. It can read images from Atari, Amiga and old Mac but to be honest I never owned an Atari nor a Mac so I mostly wanted to support images from Commodore.
Once you read an image you can save it as BMP, PNG, GIF, PNM or JPEG.
The program is freeware. You can use it commercially for free. Currently runs only under Windows but it should be fairly easy to run it under Wine on OSX and Linux.
If you have any images from C64 which cannot be loaded by Tom's Editor Desktop and you could send me these images then I would be happy to try to add support for them.
Direct link to the EXE (500 kB). Installation is not required but if you want to associate the program with various extensions it will write a bit of data to the Registry:
Games, Productivity Tools etc