Hello,
After 3 years most probably you’ve solved the problem 🙂 but that may halp for the new ones. I hope it works. Try to open the image and before doing the vanishing point, open a new window in photoshop with the video settings you want. Use default number of resolution which is “72”. Then import your original image into that window. Apply your vanishing point then export it for after effects. The vanishing point must look fine now.
Cheers,
Mehmet