Hi, RL. The advantage to using feedback for a pretest type of assessment would mostly be dependent on needing a complex Likert scale set of questions that you want to analyze for patterns and export to a spreadsheet. Since this "export to spreadsheet" feature is key for most feedback use-cases, and using imagery would get in the way of the simplicity of the current feature set in getting a clean download of the data, you probably won't see a feature request to have image uploads to Feedback added in the future.
Emma is correct that you probably do actually want the quiz module. You just need to know where the switch is to turn off the feedback for right/wrong answers, if I'm understanding your previous post correctly. See the review options in the quiz settings page for where to turn off what students will see when they answer questions. One other place to tamp down what displays on the left regarding attempt information is in the actual quiz question itself. If you look at a single question in preview mode (click the spy glass icon next to the question on the edit screen, see pic here) you will also see display options below that will allow you to turn off the points display altogether.
The quiz module is actually a pretty powerful tool for doing pretests, so I think you will like it once you get it set up the way you need it set up.
Hope those two key areas to check will help you be able to set up a pretest with images.