My front teeth have cavities near the gum line, I want veneers. Would these cavities prevent that? (Photo)

yes, u can go for veneers.  as i can see yr teeth are well aligned , but issue is with appearance.so  its good option for u.

in my opinion based on what i can tell from your photoyou are candidate for veneers.  If there is further breakdown on the inside of the tooth then the veneer could wrap around thetooth and become a crown.  They would of course still match nicely.The decay by the gumline would be cleaned repaired and covered bythe veneer.  This will help to resolve your current decay issue, howeverthere is some process going on that needs to be figured out.  Yougetting caries along the gum line may be the result of a multitude ofreasons.  If the reason is not figured out then those areas are subject togetting decay and may affect the long term results of the veneers

Cavities don't prevent you from getting veneers. My concern is that you may develope decay again at the edge of the veneer if you have been decay prone. Crumbling teeth can be restored with crowns made from the same material as veneers. This allows all of the restorations to match. I would suggest meeting with your dentist and discussing the breakdown of your teeth and developing a plan to prevent this from happening once your teeth have been restored.