I've got a image preview thing for picture files and it uses 2 methods to display a picture, if i use the /background method it loads a while (up to 1 sec), but it works if i use /drawpic -ms @preview 0 0 %scaledpicsize %fname i get the errormessage: drawpic: error loading '<picture>' the same error occurs when i load it without -s or -m.

This only occurs on very large pictures like 10000x10000

There's a good chance mIRC has a maximum buffer size for loading images. This would not be a bug, just a limitation. I'd question why you would try to load such an image to begin with. If you really need to use such a large image in mIRC, you'll have to split up the file into smaller images and load it piece by piece. Given that it looks like you're scaling it, I'd suggest scaling it to the right size *before* loading it in mIRC.

Well, thats what i thought.

But why does /background allow drawing pictures with that size and /drawpic doesn't?

/background probably just uses standard WinAPI calls which have better OS support for large files whereas /drawpic does custom drawing and image processing.