is full sized image saved as mini thumbnail after crop?

[toasty]

I have used IM to crop a photo to passport photo dimensions and uploaded it to a website needing my photo.

At first, the photo looks fine and the website accepts the photo, but when reviewing the application at the end, it is displaying a very low-resolution version of the original uncropped photo that I did not upload.

I'm not certain how the uncropped version got to the website, except that there is a thumbnail copy of the uncropped version embedded within the larger cropped photo that the website is somehow making use of.

Does IM embed a low-res copy of the full-sized photo on cropping? How do I prevent this from happening?

[snibgo]

Does IM embed a low-res copy of the full-sized photo on cropping?

No, it doesn't.

The file you processed with IM may have contained a thumbnail as metadata, and IM simply copied that to the output.

You can remove most metadata with "-strip". I don't think IM can remove just the thumbnail, but exiftool can.

[toasty]

Thanks snibgo, you're right. after a -strip, the webpage seems to display the proper crop.

It's good to know. The photo was originally taken by my DSLR. I didn't know it embeds a copy of the big photo as a thumbnail.