nightnight:
Ah sorry - I meant I edited the video to change the inserted video's link because the link you initially sent started the video at 5 seconds. Will make it clearer that it's an edit in the post :)
To answer your inserting photos question, you can use the shortcut Ctrl P or click on the image icon in the text editor (highlighted in the screenshot below), then paste in a link to the image. For example, with the screenshot below, I uploaded the screenshot to PostImages, then copied the direct link to the image. You can copy direct links to images pretty much most places I've seen :D
I haven't tried PostImages site yet, I will give it a go but which everytime I do it, it gives an error.
Edit - same error, "Something went wrong, please try again"