Rationale 1

I optimised the images in order to make it easier for users to be able to see them and if they choose to download it the images are small in size as to reduce the bandwith to make the website load faster.

Rationale 2

I would first download the image and check the size if the image is smaller than its supposed to be i would redownloaded to make sure its the right size.I would also change the file extension to a different format in order to see if the image still works correctly if it was in a different extension and rename the file to its correct name as well.Another way i would fix the image is to download it from a different source if it works then its just the server of that website which is the cause of the problem.