Then copy the URL link and paste it to your question.They all have different ways to copy the URL link. But below is the info on 2 of the most popular.
I recommend you use flickr as its part of yahoo so you’re less likely to have any problems with the link
To use flickr click on the photo then click "all size" (above the photo) choose the size you want to use then click "grab the url" under the photo and right click and paste it in your question/answer as the link below.
http://farm2.static.flickr.com/1074/1192809302_22abfa3506_b.jpg
To use photobucket click the photo and choose the size of photo you want to post then click the “direct” link under the photo and copy and paste it to your question/answer. Photobucket links can some times be flagged by yahoo with error 999.