Ranked in these QuestionsQuestion Ranking
Pro Open source
Piskel is licensed under Apache License, meaning that the user can use the software for any purpose.
Pro Works in any browser
WPiskel is HTML5-based so it works in any modern browser.
Pro Animation support
Piskel includes onion skinning, exporting to sprite sheets or gifs, defining frame rate, and present live playback.
Pro Offline versions available
The downloadable version of Piskel (built with node-webkit) is available for Windows, Linux, and Mac OS X.
Pro sleek interface
which is also easy on the eyes
Pro enough tools to be powerful
but not too many to put off beginners
Pro Very simple for beginners
Once you get the hang of it its a very powerful tool
Pro Easy to use Lighten and darken tool
with the click of a button create amazing shading
Con Rotation is limited
Rotation is only made in predefined angles. Does not support variable rotations or mouse based rotation. Does not support rotating selected areas, only frames-layers.
Con Lacks a true resizing tool
There doesn't seem to be any decent tool in Piskel for an easy stretch or shrink. The only ways possible is resizing the whole image or importing and image and shrinking it from the export tool.
Con hand by hand shading
shading can be difficult