Upload Image

Turns an image into a public image URL you can pass to any tool that needs one. If the photos are already LOCAL FILES in your own environment (the user attached them to the chat) and you can run shell commands, call upload_image() with no arguments to get an upload_url, POST the files there yourself (`curl -sS -F file=@photo1.jpg -F file=@photo2.jpg <upload_url>`, up to 10 files), then call upload_image(ticket=...) for the public URLs — the user does not have to drag anything. Otherwise: one public image URL you can pass to any tool that needs one (gbp_create_post image_url, gbp_upload_photo, upload_image_asset, upload_meta_image...). FOUR modes. (1) source_url=... when the photo is ALREADY on the web (the customer's own website, a WordPress media library, a Drive or Dropbox share link): it is fetched server-side and re-published, so NOTHING passes through the chat and the user does nothing. This mode applies whenever a URL exists. (2) a call with NO arguments returns an upload link for the user to drop files on; a call with the returned ticket then returns the uploaded images. ONE link takes up to 10 photos: they can be dropped in at once and the link stays open for 45 minutes, so several photos need only one link. (3) ticket=... to read the drop: returns `images` (one entry per uploaded file, each with its own public URL) plus `count`, and tells you whether the user can still add more. (4) image_base64=... only for a SMALL image already in the conversation — a real photo is tens of thousands of characters of base64 and will not fit in one model message, so for anything camera-sized use mode 1 or 2 instead. JPG or PNG, at least 250px on the short edge, up to 5 MB each. URLs stay reachable for 7 days, which is what image hosts like Google need because they fetch them asynchronously.