s there a mod that allows members to get a photo directly from their PC without having to use Post Image?
That's what attachments are for.
if you mean like a copy from clipboard
I'm not sure but I think SMFHacks Message Editor Pro (https://www.smfhacks.com/message-editor-pro.php) does
or SMFPacks Advanced Editor Mod (https://www.smfpacks.com/wysiwyg/) does