Hi! I made a little HTML spritesheet editor with Puzzlescript import/export functions. You can just copy the entire OBJECTS section into the textarea at the bottom and use puzzlescript->import. You can also export the entire spritesheet in a similar way. The editor supports naming sprites, and includes the default Puzzlescript palette. If you use colors from this palette, they will be named appropriately in the exported file, otherwise it will use hexcodes.
The sprite editor is size agnostic. It will import/export Puzzlescript pixel grids of any size, not just 5x5. To make it compatible with Puzzlescript, resize the canvas first. Click on Settings. Then select tile width=5, tile height=5, then press the Set button to the right to resize the canvas.
Check the sprite editor out here:
http://tmtg.net/tinyspriteeditor/Or hack it on Github:
https://github.com/borisvanschooten/tinyspriteeditor