Can anyone help, please??

Is this happening through the Dashboard on your site when trying to add an Image to a Stack, or is this happening on the Front End of the site when adding/editing a block on a page?

If this is happening on the Front End is there a javascript error anywhere on the page? If you're not sure please provide a link to the site.

Are you logged in with the Super User (admin) or are you logged in with another user?

Happening when adding a block.

I click add a block
Click add image
A screen opens however doesn't allow me to upload or browse for a photo