This list is intended to cover LibreOffice issues (not all FOSS).
That said, LibreOffice is not the software equivalent of a Swiss Army Knife. There really are things it is not designed to do. This photo editing request appears to fall into that "inappropriate tool for the task" category. I believe it is very proper to suggest alternatives in such a case.
I do agree that FOSS ought to be included in such recommendations whenever possible but each possible solution should be made to stand on its own feet recognizing that not all FOSS is created equal and that sometimes even proprietary software for a fee is best for a particular task.
Ideally every recommendation will be identified as FOSS, freeware, adware, trialware, proprietaryware for a fee, etc. Then the person who seeks help has more information upon which to base a decision.
Zeal for FOSS can get out of hand.