Help with Minimap?

That bad compression packet is annoying indeed, I'm not entirely sure why it does it if the amount of bytes is not over, but what I do is just keep editing the graphic (also was the mini-map) until it no longer gave that error. Hopefully someone will be able to offer a more technical answer to avoid it, to me it just seems like trial and error and it's iffy and tedious, but eventually you should be able to have it successfully imported without error. I guess sometimes PSV doesn't agree with the newly edited graphic enough to re-compress correctly, and changing it ever so slightly it says okay that'll work. For instance I would get the error and then change one of the mini-map colors to another or remove a certain pixel and then voilà it'd work.

Also, I hope you made a backup before this! If not you'll have to re-import the map pointers and data cause it's more or less 'bricked' once you get that error.