when i join my campaign and try to upload an image to my art library it pops up with drag and drop an image or choose a file. i choose the file but it doesn't start loading. i also tried dragging and dropping the image and still doesn't upload. the image is on my computer. the image size 7.47 mb, 4000 pixels x 2000 pixels. is my image too big to be uploaded or am i doing something wrong?