Hey there

As I have searched There is no rule regarding the orientation of thumb impression whether it should be horizontal or vertical. However the important things which are required while giving thumb impression are mentioned below:

• The impression photo size must be between 10 to 200 KB.
• The background of thumb impression must be white.
• The format of the photograph must be in JPG or JPEG only.
• In a condition where there is the eventuality of left thumb right hand thumb impression can also be used.

For more details related to NEET eligibility you can click on below link:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://medicine.careers360.com/exams/neet/amp&ved=2ahUKEwjKm6-Z6q_yAhUNfisKHeTVDU8QtwJ6BAgJEAE&usg=AOvVaw3xxBL79t8f_0su4a6OhtUd&ampcf=1

Hello,

There isn't any mention of how the impression of the thumb should be. A lot of students have this confusion, generally it is vertical, but a horizontal impression shouldn't be a problem.

Hope this helps!