You write "engineers check equipment" and "before and after testing". As noted before, this will typically be a step-by-step description of what to check, or how to test.
If documentation is needed, just put the photo-taking into the sequence as separate steps.
As there is so little information about the business in your question, I'll speculate a little: Why not -
- scan the equipment's bar code with the camera to start the process (i.e., pick the task),
- immediately after, turn on the camera to have the user take a photo,
- on next screen(s) explain what needs to be done to check/test,
- after last step, again turn on camera to obtain "after" photo,
- show the user a "review" page to verify what they are about to submit.
That way, you don't even need the user to explicitly start the "photo-taking" step, but it's integrated into the workflow and triggered by scanning a bar code (or selecting a task from a worklist) and by advancing from the last step.