Workaround: open Macpaint file in Windows 7
Decades ago I owned a MacPlus and made a few files in MacPaint, which I have doggedly copied from computer to computer, ending up on a Windows 7 PC. Feeling nostalgic, I figured out a way, albeit crudely, to get those old MacPaint files saved as JPGs.
1. Save old MacPaint file as filename.mac (.mac extension).
2. (Download and) Open Quicktime for Windows. Mine glitches when it opens and I find I have to minimize it, then maximize it again to get the full window.
3. Then go File-> Open File and navigate to your filename.mac folder.
4. change filetypes to all files (*.*) and select your filename.mac
5. Mine just opened up the MacPaint file and there it was--my 30 year old picture in all its Steve Jobs-vision glory!
6. Make the QT window as large as possible then use the Snip-it tool to save a JPG screen capture of your picture. (There may be a better way than this, but that is all I could figure out, and the original is pretty low resolution to begin with).
Alas, it only seems to work with MacPaint files. For MacDraw files I was able to open them in Adobe Illustrator, although the fonts and some of the lines were wrong. Not bad for 30 year old files though!