Delhi

The top five colleges in New Delhi for pursuing MBA/PGDM are as follows:-
1. FMS
2. IIT Delhi
3. IIFT
4. IMI
5. FORE.
Kindly visit this link for more details: https://www.shiksha.com/mba/ranking/top-mba-colleges-in-delhi/ncr/2-2-0-10223-0

It depends on what you want from that Institute and how much spare time you have for learning photography.
Finding the best photography institute is the challenging task. The institute should have good grounding in aesthetic, technical and professional qualities so that students can get more exposure.
According to me I find The Wedding Film School as the best institute in Delhi since it provides good professional short-term certificate based courses. Their main focus is on practical exposure which is required most to master the field.

Heritage Institute of Management and Communication is better than IIMMI for BMC course.

Yes, you can but college change or university change after first year is completely dependent on college and university norms, some university allow it and some won't plus you need to have good scores in first year to apply for the same. For further details contact the college authorities.

If you want to get admission in ISI then you must sit in the entrance exam of ISI.

You can refer to the below mentioned link for more information on the colleges: https://www.shiksha.com/teaching-education/colleges/b-ed-colleges-delhi-ncr

Career opportunities include professional practice with newspapers, magazines and digital media houses; empanelment with select advertising agencies, brands, corporates, industrial houses; freelance in their area of interest such as fashion photography, advertising, portraiture, architecture, wildlife photography and documentary.
Photographers are at times get paid a certain amount of money for each picture that they shoot or paid an hourly rate or salary. Their earnings or salaries can vary depending on their experience and talent.