Images that you use on Steemit can be yours or free attribution images.
You can not use the images that are under the strict copyright.
Screen captures or the images from the movie video trailers are excluded, as the first is an original capture by you and the second is an advertising material which is free to distribute.
You can also use freely the Youtube videos in your posts. They are not questionable.
Your own image should be either an original art, photo, graphic or composite (wallpaper, poster, banner) uploaded directly on Steemit or hosted on the outside host service.
If you host your own image on the outside host (imgurl) and pasting it with a code, you do not need to source it with the link. If you decide to download your own image or free attribution image, and then upload it on Steemit, you have to resource it with the Source link to the original picture.
If your original image is protected by teh copyright, you have to verify it is yours.
You can host your images on any external host ( Imgur, Facebook, Twitter…) or directly on Steemit ( upload).
To source an image means that you have to paste a direct link from where you took it.
Paste this code in your Markdown editor in Steemit and substitute the “URL of image” with appropriate link.
[Source](URL of image)