There's lots of ways to upload a picture, but I'll just explain what I do. There's always the option of taking a cell phone picture, emailing it to yourself, and then downloading it from your email. What I prefer to do is use a scanner (if you don't have one, a school or library usually will).
Artist block isn't something you can choose. If you need a breather from drawing, then take it, and in the meantime study other art and let the ideas and concepts float in your head for a while until you feel the need to draw. If you need practice, then take the 'inspiration' out of the equation, and simply do some personal art studies. Take a brown paper bag, crumple it, and draw it (great practice for shading and form.) Look up pictures of things your interested in drawing, and draw them. Focus on the technical aspect of drawing; shading, form, proportion, contrast, etc. That way instead of fishing around for an idea of what to draw, you're successfully using your skills and still drawing, while getting better.
Hope that helps!
