Hi Bardon,
Thank you for your question. It can be a bit hard to find licence-free pictures. However, there is a commercial free BSL font from Commanding Hands.
If you're happy to make your own images, you could use online BSL dictionaries and pause the video at a key moment to help with creating your own BSL images. With more time this technique can also be used for creating animations too.
For instance this is a BSL gif for toothpaste I made a while back through the use of dictionaries.
How many words do you need images for?