That's 100 words on your actual pictures but you could include a thumbnail of an image you'd seen that gave you a idea (as they say a picture is worth a thousand words!) and a short paragraph on what has struck you after your background reading can go right at the start.

What you submit and what you write are not necessarily the same – a pull quote from your own thoughts (where you take something from your thoughts that really sticks out) is very useful - it's good to keep it brief is because it does help you focus on what was most important in each case and it's the same with background research. Those pithy thoughts tend to stay with you – and that’s useful.