I have app, that opens image and redraws it with opengl as textured quad. This app works fine on iMac with AMD Radeon HD 6750M but when I launch this app on iMac with nVidia GeForce 7300 some images is not correctly redrawn. For example some images with 3200x2000 dimensions it redraws as a quad with identical edges (top and bottom is equal to right and left). Could it be problem with OpenGL code? Or my mistake should be in Objective-C code where image is being processed before sending it to OpenGL?

P.S. I have no ability to test it on macs with other graphics card but as I see this problem is on almost all older macs.