Cannot load jpg

Since some days I cannot load jpg pictures. I did not change the code.
Same code works with windows.
It is a web app.
I tried all ubuntu derivates, mageia and suse linux.
I can load png pictures.

How do you load a JPG? Do you use:

myPicture = Picture.Open(f)

It was my mistake. I renamed a folder with uppercase letters, forgetting, linux make a different between uppercase und lower?ase letters.
The png files were in a different folder.