I have enjoyed creating games and apps with knp/clickteam for years and years, but one of my only frustrations with it is drawing the game art. The inbuilt editor misses many features to allow it to do anything more than tweaks. That is why I created onsprite.com.
This is a free online tile and sprite creator (which can be found here: http://onsprite.com/tile-creator.php )
Resizable Brush Tool and Eraser
Eyedropper and Paint Bucket
Resizable Line tool and Shade Brush
Layers and transparency
See the tiled and scaled image as you draw
Auto Shade and Tint as you draw
Save and Load image projects to and from any computer
Export your images at a click of a button
Use the images for whatever you want including commercial uses!
Let me know what you think!