Palette changer tools?

[Davy Jones]

Source and destination have the same size - I don't see a point in different sizes as it's only comparing pixels at the same relative positions.

It's not about the size, it's more about the chaotic control over two frames at the same time. I have no idea how to handle these things.

The picture just shows a graphic program, in which you can mark a sprite as a source and then controlling the destination frame. Not both at the same time.

Edit:
For the performance: It seems like the loupe has something to with it, the more I zoom the more the frames lag. The performance seems to be okay on normal resolution.
Edit2:
The sheet size is also responsible.
Edit3:
Sheet size 381x381. Normal resolution: Fluid. Zoom: Lags.
Sheet size 512x2048. Normal resolution: Lags. Zoom: More lags.

@puggsoy: Dragging rectangles would be wonderful.

All in all, these tools are going into the right direction =)