I have a problem displaying with Ribbon images with correct size using Revit API. It seems as if (for some images) it truncates several pixels off on the bottom and right side. For other images, it's fine. I can't figure what we need to do to correct this problem. Do you have any suggestions?"
One possible cause is the resolution of the image. Implementation of Ribbon uses WPF. It uses 96 as the default dpi (dot per inch). So, when the image has a resolution like 72 dpi, the image will be bigger under 96 dpi.
If you are experiencing problems where an image looks like being "scaled", you may want to check the resolution of image. To check the resolution, you can use Paint program, for example, then go to: >> [Images] menu >> [Attributes]. Simply saving in the image in Paint program, for example, will change the resolution and may fix the problem.