There is very little to work with.
Can you give details of what it is that you are doing ?
A screenshot of the Avast alert with the Details option enabled could help. - Attaching Images to your post - When you Click the Reply button it opens a text window for you to post your comment (reply or post).
Click the Preview button, that shows what you have input and expands it to include 'Attachments and other options'. Click that it further expands, here you can attach images, etc. at the bottom of your post.
See my attached image, click to expand.
