Caching query

[davestevens_uk]

Hi there,

Hopefully someone can help me with this one. I have a photo album on my site which I upload thumbnails/images to, with navigation built around a MySql database. Basically, you navigate to an album of thumbnails, and clicking takes you to the full size image – pretty standard stuff.

I’ve recently starting playing around with GD for resizing, and also the concept of protecting the images. Basically, I’m now calling the thumbnails via a script rather than a ‘real’ file location. So, instead of this:

<img src="./glasgow_2002/AA_0_A01-t.jpg"
I have:
src="./thumbnail.php?RollID=glasgow_2002&FrameID=AA_0_A01

thumbnail.php does a couple of things:
1. Checks whether user has correct permissions to view that thumbnail
2. Gets the image (stored outside public document root for security) based on the query variables
3. Resizes the image and spits it out via a Header statement.

That all works perfectly, but my problem is that the browser (IE) does not seem to cache the src retrieved by thumbnail.php. This means that every time you go back to the thumbnails page, they all load dynamically again, and this makes for a poor user experience. Strangely, Opera does seem to cache them fine.

Any suggestions on how to force IE to cache?

Thanks,
David

[drew010]

there are options you can send in headers to tell browsers to cache, but the user's browser settings will override this. for example if a person has i.e. check for a new version of the page on every load, it will ignore cache requests.
look at meta tag expires and meta tag pragma which can instruct the browser to cache.

[davestevens_uk]

Thanks Drew, I'll have a look at that.

I think the problem is that IE doesn't even see the output from the .php script as an image. e.g if you right click and try 'save as', it just comes up as 'untitled'.

Anyway, I'll keep looking!

Cheers,

[drew010]

im not sure ie wanting to save as untitled has to do with your php script. a few months ago when i.e. upgraded it started doing the same to me no matter what image i tried to save. i dont know if its a copyright thing and ie only saves images as bitmaps to make it difficult for some people to get them to web graphics (gif jpeg) but once that happened i stopped using ie completely and went to mozilla which saves all images fine. good luck with it