I wanted to support more disk image formats in MartyPC, and be able to run copy-protected disk images. To that end I started making a disk image library, which I call fluxfox.
https://github.com/dbalsom/fluxfox/

It now has a GUI interface, which you can try out here thanks to the magic of wasm:
https://dbalsom.github.io/fluxfox/

You can drag disk images into the browser window to load them. Bitstream and higher resolution images will produce a visualization, like so, which you can save to PNG.

The desktop version will support kryoflux images, but they tend to crash the web version at the moment. That's all well and good because my flux support still has a long way to go to match the quality of existing tools like HxC and Applesauce when it comes to resolving raw flux. You may get some single-sided dumps to load - if you crash it, no big deal, just reload the tab.

One cool feature I think unique to fluxfox is the ability to visualize files graphically, as either 1,2,4, or 8bpp raw bitmaps. Here we can see that the SCREEN file in Wizball is formatted to be dumped directly into CGA memory. MartyPC has this tool as well, and the advantage there is that the emulator can provide the device palette for 8-bit images, but no such luck here. I'll probably end up adding a few standard VGA palettes, or maybe let you upload your own. They're tiny and we could cache them in localstorage so they'd persist from session to session.

MartyPC will eventually inherit all of this, but I figure it has some usefulness as a standalone utility - the web version is particularly neat because it's automatically cross platform and hassle-free.

I'd love to hear your comments and suggestions.