i need a code for php changing image in every 2 hours at a time ...

Independently for each user?

Avatar cereal no independent its commmon for all users

Actually i was save images are seperate links so i want to use <img src=""> instead of these links ...

how many images?
1. say, will they be like 2 alternating images sequencing two hours intervals.
2. every two hours in a day a new image (that makes 12 in total) to be shown as hours pass.
3. fixed in client time of application use, or in UTC Time of a local user?

how would you expect anyoe to be able to respond correctly if there are so many modalities involved, could you?