@alok_ranjan_Sahoo Please make sure that the images you are using are of requested format and size.
If the dimensions and format of the images are correction, please try uploading the images from different browser or device. I will suggest you to upload the images in not busy hours like late night or early morning.
I hope these will solve your problem. If it still persist please let us know.
@Manoj_Khan AIPMT web server is not performing good. You may see error on the website many times. However these are just temporary errors and site works after some time. Also AIPMT website generated a session to which does not remain active if you open another page while submitting the Application Form.
Please do not open any other page once you are on application form page. Also try different device if the site is not opening on you computer / laptop.