Yes, but these are only the labels for the form. I'm interested in the wikitext that ends up in the page source.
Please provide a picture from Commons for clarification
Picture of what,wikitext? [[File:Example.pg|left|thumb]] Parameters like "thumb" and "left" can be translated, but I am not sure how.
You can find these in MediaWiki core: $magicWords array in languages/messages/MessagesXX.php.
languages/messages/MessagesXX.php