I faced with unclear situation and need your explanation. I have scanned document with some weird images - Adobe Acrobat shows boxes around them:
boxes.png (5.9 KB)
Aspose.PDF also detects 4 images. But when I want to extract them via Adobe Acrobat, it says following:
noimagestoextract.png (5.5 KB)
After deep investigation I’ve noticed they are 1-pixel transparent images, so assume Adobe skips them because of this.
Please explain what they are. This is sample document (72.0 KB)