Most Helpful Girl
Well if you're struggling with this I'm sure you'll need help with the other things that fall under this category so it's better to explain them all now...
Well it depends on if you're referring to your profile pic or posting a pic on an opinion or question.
Profile is very easy you just click on it and use any pic that you have on your phone or computer to make your profile pic or background pic on your profile. (Click on my profile to see what I mean).
As for the other ways to post pics you have to be a certain xper level to post links to pics or videos, but I'm pretty sure you passed that level.
Let's use ice cream as an example. Go to google images type in icecream click on the image that you want then press view image. Once it's full screen copy the link and post it on GAG.
But you have to do it on your answer and not your content or it will appear as a link. Also you're limited to three post if it's more than three then the rest of them will appear as a link.
Now when if you would like to post a video of song or whatever else the video is of can go to YouTube look up the video or the song and once it pops up at right under it you'll see a plus, something that resembles a greater than sign, and a report/spam symbol. You're going to click the middle one and it will pop up Google+, Twitter, Facebook, email, and SMS. But above it you'll see a link so you just click on it and copy it then you'll paste it for your opinion or question. Again if you post more than 3 it'll begin to show the link instead.
Last but not least if you ever wish to leave/post a picture of yourself as an opinion or your question you're going to have an account like Photobucket, TinyPic, or Imgur. You go to your profile and copy and paste the direct link to that picture of whatever pic you would like that you uploaded to your account. But once again we're limited to three so once it's past that the links will begin to appear.
s1378. photobucket. com/user/MonaeAllDaWay/media/Mobile%20Uploads/IMG_20150404_210256_zpsdmjowr3j. jpg. html
And that's all the rules to posting a picture on GAG =)0