What does it take to take....
We have all seen the original with the huge t-rex chasing the bridal party ...and of course if you have shot a wedding on planet earth in the past 6 months you have had at least one request to recreate this image.
Best advice I have for you is to cover this stuff in advance with your client so they understand the additional work (and cost) these images take. It is not as simple as just lifting the original dino out of the image and plonking it into their wedding photo.
So what goes into creating such an image??...Well firstly, let's visit copyright infringement, you have to make sure you are staying within the law when creating such an image.
Then of course you need to find a dino that has a clean background to make it easier to cut out and layer into the wedding photo...Oh and the little matter of it being big enough...if you are not working with at least 1000px across you are going to get a big old ugly pixelated mess.
Then lighting...you have to match lighting between the two images...if you are lucky and find one that match at least some..but you are still going to have to burn/dodge and brush them until they match perfectly...and that goes for the edges as well...you need to make sure there is no residual "old background" surrounding your dino...well that is unless you are trying to recreate the B movie effects of the 70's eg: Godzilla lol.
Then you have to find just the right placement within the photo...where are the majority of the wedding party looking...ok so that is where the head of the dino needs to be.