The format is correct.
When you paste images, they go to your vault as new files. Do you find them in your vault? Can you open them?
Can you go to Settings > Files & Links and show what’s in your definitions?
Go to your (computer) file explorer system and find the image in your vault folder (where you place your vault in your computer system).
There try open/preview your image.
If image ok, back to Obsidian and try two things:
1 - open the help vault and place an image there;
2 - if everything works normally in help vault, return to your vault and check every extra: change theme to default; disable plugins; disable any css snippet; etc.
Awesome thanks. I tried it out in the help vault and it worked, which means I must have done something weird with the settings on my vault by accident. I just started using obsidian today, so I found it easier to just make a new vault and copy and paste everything rather than trying to find the setting. I really appreciate your help.