Hi,

It's in your directory structure:

Small
/public_html/catalog/images/Sweet ZouZou/file.jpg

Medium
/public_html/catalog/images/Sweet ZouZou/medium/file_MED.jpg

Large
/public_html/catalog/images/Sweet ZouZou/large/file_LRG.jpg

Should be:
Small
/public_html/catalog/images/Sweet ZouZou/file.jpg <--This one is OK

Medium
/public_html/catalog/images/medium/Sweet ZouZou/file_MED.jpg

Large
/public_html/catalog/images/large/Sweet ZouZou/file_LRG.jpg