1 pixel will import into solidworks with a size of 1mm.
If you use a transparent image format like PNG, it won't matter much. But you can resize the image once it is a label. Just make sure to maintain the aspect ratio.
Search the help file for decal. I think SW2012 allowed for decals, but I can't remember.
If you are doing a rendering, I'd apply the decal in the rendering program.
Thank you for your time,but I found a problem about decals.What about pixels and length and width?
that's the biggest problem there.