I don't know if anyone else has thought of this but I figured I'd put the idea out.
I'm working on a plugin project and found it difficult to make the images using the pixel editors (Pixly & Draw Pixel Art). So I decided to start bigger and used Microstation (it's a CAD program which can do 2d and 3d, for those who don't know) & GIMP on my computer. I could have also used 3DS Max (for making 3d models) but I can be more accurate with measurements in Microstation.
So how I'm doing it:
- Bring in the 8x8 image tile as a 'Raster' (since it's the largest tile and can also be used as a reference for the smaller sizes) - it can be sized as needed for modeling
- Use the image (in isometric view) to create the item(s)
- Apply textures to item (Microstation has LOADS of textures available or you can use your own)
- 'Capture' and save the item as a PNG screenshot
- Open the image(s) in GIMP
- Clean image(s)
- Bring in appropriate #x# tile as a layer and scale it up to 10x its normal size
- Scale up your image layer(s) to fit the tile
- Apply borders and such
- Export full image (again, as PNG)
- Bring that image back in to use for shadow
- Make it completely black (the non-transparent parts, if course)
- Make the Opacity 25% (my preference, of course) then use 'Perspective' tool to adjust it appropriately (maybe even scale it down just a bit)
- Export the new PNG image then save GIMP file for possible later needs
- Bring it into its own GIMP file
- Scale it all down to the #x# tile's normal size
- Export as the file you'll be using for your plugin
Maybe it's not an idea everyone would want to use. But for those (like me) who find it difficult to work at such a small level the regular way this might be worth trying.