We take it that the file or image is "stored" in a folder on your device in say file explorer. If so when you are composing an email or replying to one in BT mail you will see a little paperclip icon with Attach written next to it bottom left of he email page. Now, Left click that once and it will open file explorer. File explorer is diveded up into various folders like pictures, documents, downloads, etc etc. If you have put the document or file into documents then click on documents and find the file that is the one that you want. RIGHT click that file and choose SELECT from the top of the pop out list that appears. If it was a document that you have downloaded it will be in the downloads file, pictures in the picture file and so on. After choosing SELECT go back to your email tab and it will be sitting in the email dialogue box as a jpeg that can be opened by the recipient.