Let's narrow it down in the terminology department since that's the first area that we can narrow down.
Go to any page to see a picture you want to post. If you search for images by topic such as on google? you cannot get the code from the thumbnails page. You actually have to open the image.You can do that by right clicking on the thumbnail and then choosing open in a new tab or choosing open in a new page.
Hover over the image and right click on either "view image" "copy image location" or "copy." If you choose view image, the code in the address bar will change. you have to copy and paste the address from the address bar to the site.
You do that by having your new blog page open. you can respond/comment with a picture on someone's blog in the same way.
just above the message portion of the blog (below the title if you are writing the blog) see those little symbols above where the text would be? B I U abc, etc?
Left click and open the one far right and it will open another window.
Paste the address from the address bar of the page the picture was on or the image code if you chose copy address in the top line then click ok. The picture will show up in the message area. Then click publish. If it doesn't appear when you click ok, something went wrong.
If you want to post personal pictures you have to have a code. You can open a free photobucket account or upload them to your facebook page and then do do view image and copy the code from the address bar and do the same process as above.
This code only works on the blogs. If you want to post an image on someone's page, you have to get the HTML code. I do that from my photobucket account.