Non-Hack Tile Editing

[Phazar]

I've recently started using RPGMaker, and have reached a stage where I am thinking about graphics editing in my current project.  Does anyone know a tool similar to Tile Layer Pro that can edit non-hack, regular PNG-form tilesets?  Because sadly TLP cannot read them in a form that isn't random gibberish, but I would love a similarly easy-to-use tile editor that works, ideally with TLP's "edit tiles in four pieces" function.

[Zhs2]

I think Tile Molester can edit PNGs? YY-Chr as well? If either of those fail, however, I recommend this: http://www.aseprite.org/

[Lunaria]

Woah, woah, woah, wait a second... YY-Chr can be used for .png editing?

[Phazar]

TM doesn't seem to work.  Haven't tested YY-Chr yet.