Picture size....

Is there an "optimal sized photo for uploading here? Recently started shooting images in RAW and editing them. From what I have seen, at least in regards to a few different sites, Facebook being one of them, 1200 pixels x 630 pixels seems to be a good size in order to avoid the sites software from doing its compression....

Its less about dimensions and more about 'weight' of the image. Images have 2 basic size specifications. One is what you mentioned, the height x width in pixels. The other is how much space they take -- usually represented as a single number eg 5mb. The larger this number is the longer it takes a user to download the image and the more storage space it takes to save on our servers.