Src (tag)
From SnapMap
src=<url> is to point to an actual image file for the image. The URL must be fully specified, including 'http://'.
No hard rules, but consider this version, in comparison with thumbnail (tag) and src_largest (tag), as being the default version to show on a typical web page. In other words, taking Flickr and Wikipedia, and many online stock agencies, as a guide to how to present individual photos, their longest side should be around 500 pixels. For casual photo browsing, src and thumbnail should be all a user agent needs to worry about. News websites often use a photo of this kind of size at the top of their articles, as in the example below.
Example
src=http://www.timesonline.co.uk/multimedia/archive/00629/winner585_629478a.jpg
