4, the size of the control. We know that for certain types of map.
, the deployment of relevant information of the picture. We often in some large portal sites, often see some popular atlas, atlas under each picture will write down the description information of the pictures, some pictures with the keyword matching text in bold display. In fact, according to the current technological development of the search engine, "if only simple images, search engines can only index to the general web Title and other related information and pictures of Alt description. So, if you can put some pictures in the front and rear position for picture text, picture or description information with keyword matching to optimize the picture, web pages can be better in the search engine rankings.