How Come I Keep Losing Storage Space?

So I have a blackberry torch and at on point I had around 2000 photos a few videos and quite a few apps then I ran out of space and deeted like hmm over 1000 pictures quite a few apps and most of my videos so now my storage space has gotten really small I have only around 200 pictures like two videos and only essential apps and it says I have only room for one more picture now keep in mind I don’t have any conversations or anything saved so why do I have so little storage space (and say I have no more room for pictures I delete around 6 and it only gives me 1 or 2 more pictures) and why does it keep lowering