When I wanted to upload image, I've always been downloading image and manually uploading it on TalkImg until today and I feel so stupid for not doing this before. As it seems, you can copy the image in the browser and then paste it on TalkImg. The image will automatically be uploaded on TalkImg, so no need to download and reupload them manually.
I don't know how many people know about this but I think that it is a nice idea to give them a hint, i.e. write somewhere that users can copy and paste the image on TalkImg. This will help people to not download and upload it like me, it will save them some time.