Cherry!:) One you click Edit Photo, and you go to that link you included here, you are meant to click on the yellow box on the right, on the little button that says something like "examine" (I don't know what language you use Italki on, so that depends) and there, you select the picture you want to use. If it doens't allow you to use a certain picture, is because the format of the picture (bit map, gif, jpg, jpeg) is not compatible with the formats allowed by Italki:) You can try to change the format of the picture or just select another one:)
Much love!:)
Ana:)