Why capture the pawn in this scenario?

One of the areas I’m trying to improve in is knowing when to capture or push a pawn. I understand the basics (i.e. material gain/ improved position/ more space) but sometimes struggle to make the best move in practice. Can someone explain why in this picture capturing was a better move? Thank you!

Trying to figure out how to post the photo...

I'm a beginner myself, however I can see that if you capture the pawn on c5, then your opponent captures it, you can then move your pawn to c4. Note that your opponent cannot take your pawn on c4 because if he/she does, you can capture the knight on c6 and the opponent's king is in check and you can also capture the rook on a8. 

 

So your opponent won't capture your pawn on c5, but will move something else, but then you can capture the pawn on d5. If he tries to capture your pawn on d5 with the knight, you can capture it with your bishop, then he captures it with the queen and you capture it with your queen, so he won't capture your pawn on d5, so you can win a pawn.

 

Maybe there's also something else I missed because as I said I'm also a beginner, but that's what I saw.

I am a beginner too, but just generally speaking, strategically, white has the bishop pair and black’s king is in the center, so opening the game seems to make sense...

My guess is blacks pair of knights favours a closed game so black might try to push with c4, closing the centre and gaining space on the queenside. They could then try to push the a or b pawn to open a file or create a target. Black could also try and trade off the LSB which would further weaken d3 which they might be able to use later in the game. White has castled, black has not, and has the bishop pair which favours an open game so trading off central pawns So dxc advances whites agenda and frustrates black. I'm no expert, so just sharing some ideas.

just on basic fundamental rule of thumb thingies...

as white when you have castled and gotten solid/rapid development and black is still lagging (black needs 1 and most likely 2 moves before castling- black really doesnt want to queenside castle does it?)

it is a good plan to open up the position especially when whites position is so nice (look at those bishops just eating up the queenside)

dxc5 can only be immediately recaptured with a developed pawn so the opening up is even more direct and forceful

it is not like white is going to checkmate in 5 moves (though if black really feels pressure or completely ignores things it can get ugly quick) but having a plan is a hard thing to do in chess so when a really good plan to have is to open with dxc5

it is not like the other move is a blunder- position is still good but when one can make strong moves like dxc5 then games go better than missing it

Opening the center is a good idea, and I'm an intermediate. However, the e file hasn't opened, the light-squared bishop is limited, so white might have an advantage, not because of move ideas, but because of piece advantage.

Of course, I might not be correct...