Image Handler 3 Support Thread (for ZC v1.3.9)

[hara]

So clearly you misunderstood that uploading mismatched filetypes is problematic.. (hence why "Image Handler3 will display mismatched file extensions in red in the additional images table")

Even I upload mismatched filetypes, I don't see in red in the additional image table as readme said, but error message instead. This also confusing me.

Anyway, found the problem. Thank you all!