Well, it seems that this only mitigates the problem. Found jpeg corruption, in a fewer number of sites though.
Hi, had same problem with Safari 16.5, MacOS 12.6.6. Disabling both, Lazy iframe loading and Lazy image loading, did not solve the problem.
Disabling "GPU Process: Canvas redering" and "GPU Process: DOM rendering" in Safari->Develop->Experimental Features solved the image corruption.