If I understood this correctly: you want to overlap a transparent photo over another photo. But the overlapping area should show only the photo on top!
I assume for some reasons you don't want to switch off transparency effect of the photo to achieve this?
And you also don't want to send the transparent photo to the back of first photo so that for the overlapping area only the first photo area will show then?
If this is the case, you can try using a custom shape frame for the photo beneath:
1. Place both the photo the way you want them to overlap at corners
2. Select the photo on top and Copy (no need to paste now)
3. Select both photos, go to Window > Object & Layout > Path finder and click on the Subtract button
You got the photo at the back in a custom shape frame minus the overlapping area
4. Now Edit > Paste in place
The transparent photo you copied is now precisely aligned to the custom shape of the first photo frame
Thank you so much for answering. I'm very new and actually have no idea how to switch off the transparency of a photo, but that would probably fix my problem, then I could send to front/back accordingly. Can you please advise? I have tried to send the photo I edited to be transparent to the back but the overlapping space is still blending.
I used your numbered method with the custom frame and that worked. Thank you!
To detect and discard transparency: First check if the transparency on the image is caused by any settings in ID:
1. Select the image frame and go to Object > Effects > Transparency. Make sure the opacity value here is 100% and no other effects applied
2. Direct select the image (i.e. the image, not the frame. You can use the white pointer tool to direct select the image), go to Object > Effects > Transparency. Make sure the opacity value here is 100% and no other effects applied.
3. If you are not detecting any transparency setting by the above methods, then your image has a transparency from source. You need to open the image in Photoshop to detect this and save without transparency. Saving jpeg will automatically discard transparency. If it is png or other similar formats you need to switch off all transparency layers and flatten the image, save and then place in ID.