When reproducing an excerpt from a text identically (and properly referenced), we are quoting it 'verbatim'. Is there an equivalent term in English that refers to reproducing an image faithfully? I would like to use a construction along the lines of: 'His reluctance to quote his own artwork [MISSING WORD]...'
In the world of photography, a piece can be retouched (M-W link), meaning "to make small changes ... in order to improve the way it looks." When all photography was done using silver-halide on gelatin, the manner of doing this was an airbrush (Wikipedia link). In digital photography we can use software to do retouching, such as the common PhotoShop.
Apparently, the term retouched can also be applied to paintings. An article describing a famous example of a botched restoration (FoxNews link) makes use of the term.
So, to describe an image which has not been altered or improved in anyway, the term is unretouched (Collins link).
In your example, and borrowing from a previous answer, I would phrase like so:
His reluctance to use unretouched copies of his own artwork...