What are the optimal pixel dimensions when uploading my images in Media? I mean the largest size they will ever need to be, because this is the size I should upload my pictures in, right? I want the image quality to be as good as possible but with a normal & reasonable loading time.
The recommended image size is 2100px by the bigger side. Basically the theme will create copies of the images you upload in several sizes for use in different places. The biggest of them being 2100px by the bigger side.