Cached, PHP generated Thumbnails load slowly

Question

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Main question was how to make this site, load faster. First we needed to read these waterfalls. Thanks all fo

Answer 1

First of all, you need to handle If-Modified-Since requests and such appropriately, as James said. That error states that: "When I ask your server if that image is modified since the last time, it sends the whole image instead of a simple yes/no".

The time between the connection and the first byte is generally the time your PHP script takes to run. It is apparent that something is happening when that script starts to run.

1. Have you considered profiling it? It may have some issues.
2. Combined with the above issue, your script may be running many more times than needed. Ideally, it should generate thumbs only if the original image is modified and send cached thumbs for every other request. Have you checked that the script is generating the images unnecessarily (e.g. for each request)?

Generating proper headers through the application is a bit tricky, plus they may get overwritten by the server. And you are exposed to abuse as anyone sending some no-cache request headers will cause your thumbnail generator to run continuously (and raise loads). So, if possible, try to save those generated thumbs, call the saved images directly from your pages and manage headers from .htaccess. In this case, you wouldn't even need anything in your .htaccess if your server is configured properly.

Other than these, you can apply some of the bright optimization ideas from the performance parts of this overall nice SO question on how to do websites the right way, like splitting your resources into cookieless subdomains, etc. But at any rate, a 3k image shouldn't take a second to load, this is apparent when compared to other items in the graphs. You should try to spot the problem before optimizing.