now we want to start a photo gallery site , can i use adsense or some other cpm advetiser like fastclick,casale etc
Sure. Photos qualify as "content". Just don't forget to add text caption and alt tags to help you focus your ads. As with CPM, yeah, you can use them, but you need to apply and get into them first, and if your site is just a photo gallery, the top tier networks like Fastclick (Valueclick Media now) will be difficult to get into. Good luck.
What kind of ads would be relevant to photos? I don't think if that is enough content, but I could be mistaken.
@Philky, it really depends on the kind of gallery and who the OP's target market is. Jack's completely right about how to give content for serving of relevant ads. You should also consider section targeting so that the attention is focused on captions and alt text.
If you have pictures of a Labrador dog and the pic is titled properly, then it will pull ads handsomely. Likewise if you title the pages 'us on holiday in Antigua' likely you will pull holiday in antigua ads outside our 'florida holiday villa ' etc.
Yes, as the others said. Labeling your pictures and the page they're on is of utmost importance if it's just a photo gallery. Things to remember to label correctly (as in the kind of ads you want to attract): The page title. The picture file name itself. Alt Tags. Caption underneath/above picture to further reinforce your keyword. Do all that, and you should get relevant ads for your pictures. You'll get the usual generic "picture gallery" or "art gallery" ads in-between the really targeted ones, but more often than not you should get relevant ads.
I have a website that is focussed on Travel Photography. All web pages have images as well as content (text) in the form of a description of the image or the gallery as well as alt tags for images. I have seen that Adsense always serves contextual ads on this site so if you have a photo gallery, just make sure that all images are alt tagged. Remember, you alt tag doesn't have to be one or two words, you can actually have a sentence or so about the image. Also, it will be much better if you can display a description of where/when the image was taken above/below the image. Forget Google, this is also much better for your users as they will know a bit more about the image. Regards, dfsweb