Drag and drop doesn't work because it's not supported by the internet browsers - it has nothing to do with this site. Here are the faq's on uploading pictures:
Here's one on how to upload a picture directly into the forums:
https://www.turbodieselregister.com/faq/index.php?act=Answer&cid=41&id=29
In order to do that the file will need to be under 32,000 bytes in size.
Here's one on how to upload a picture into a reader's rigs album:
https://www.turbodieselregister.com/faq/index.php?act=Answer&cid=41&id=30
In order to do that the file will need to be under 122,800 bytes in size. Once you upload it to the reader's rigs album there will be a link under the picture that says "forum codes" - click on that and it will show you the exact code you need to type into a message to post that picture in a message. Then right click inside one of the fields and then click on select all then right click on the highlighted text and click on copy. Then go to post your message and where you want to put the picture right click and click on paste.
If your pictures are larger than those file sizes you will have to reduce them in a paint or photo program. Paint is included with windows and will work and there are others (Adobe Photoshop is a popular one). If you resize the image to 320x240 and save it in jpg format you should be under the 32,000 to post directly in the forums. If you resize the image to 640x480 and save it in jpg format you will definately be under the 122,800 to upload it into the readers rigs section.
In anticipation of your next question the reason for the file size limitations is because of download time for users on dial up connections. The reason for the smaller file size limitation in the forums is because of the way that data is stored in the forum software - larger photos store directly in the forums would put a greater load on the server.
Hopefully this helps, if you get lost along the way ask away and I'll do what I can to help.
-Steve St. Laurent
Webmaster