A large visual is not automatically an understandable one. A photograph may fill most of a slide while leaving the important object hard to recognize. A chart can be exported sharply but still have a tiny legend. Evaluate each visual by the information the audience needs to identify, rather than by how neatly it fills unused space.
Give every visual a job
If a screenshot documents an error, the error message needs to be readable. If it explains a path through an application, nearby controls may also be necessary. Those purposes call for different crops. Do not crop so tightly that the source or meaning of the detail becomes unclear.
In a photograph of a workstation, cable routing might be the actual subject. Remove irrelevant edges instead of shrinking the entire room onto the slide. Before using the image, check for names, identifying details, or confidential screen content. Covering information with a decorative shape is not a dependable way to remove it from the source file.
Check size, sharpness, and contrast
Avoid enlarging a small raster image until its text and lines break apart. Use a higher-resolution original or a suitable vector version where available. For a chart, rebuilding a simpler view from the original data may work better than taking a screenshot of the entire spreadsheet. Preserve the values and labels when simplifying it.
Do not place text over busy areas of a photograph. A separate label area is often clearer than a heavy outline or drop shadow. Also consider lighter and darker viewing conditions. Fine gray lines that are visible at your desk may disappear in a meeting room or compressed screen share.
Inspect the delivered version
Open the exported presentation or PDF and pay particular attention to detailed slides. Compression, substituted fonts, and changed crops can become visible there. Check important graphics at the smallest intended viewing size, such as a shared meeting window, rather than judging only the full-screen editor.
Write a short description that conveys meaning rather than merely listing objects. For a chart, that might be the main trend; for an instruction, the position and purpose of a control. If several exact figures are necessary to understand the point, supply them as readable text or a table as well. The visual should make the explanation easier to access, without becoming its only route.