This is usually correct behavior rather than a failure. The app skips any image the run would not change, such as one already at or under your target, so a run over a mixed catalog legitimately reports fewer images changed than images scanned. An image is left alone when your settings would not change it: it is already within your maximum dimension or frame and already in the output format you asked for, or, in Target file size mode, recompressing it would not make it any smaller.
Check these in order
Open the run in History
The run shows how many images were changed and how many were skipped.Read the reason beside each skipped image
Most say the image was already this size, so there was nothing to resize.Check your resize mode
Longest side and Fit inside only ever shrink an image that is bigger than your target.Check your watermark, if you asked for one
A skipped image in a watermark run says whether the logo could not be read or no watermark was set.
How to fix it
If you genuinely want every image brought to an exact size, even the small ones, choose Width and height with the Crop to fill the frame or Pad to an exact size fit style for that run, and expect the chargeable count to rise accordingly. If a watermark was the problem, upload the logo again on the Watermark screen and re-run.
If it still is not working
Send us the batch and we will read its per-image outcome: contact support.
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