php and images

[Anon]

i have looked at some of the php codes for thumb nails, but they seem to resize the image at the <img> tag.

does that really redue the file size and load time?
or can php reduces that as well?

[Anon]

No, changing an image size by specifying it in an IMG tag is not resizing, but scaling. The browser still has to load the image at original size, but is told to render it on a smaller scale.

PHP can me made to manipulate images through the GD lib if it is installed, or some other image software such as ImageMagick.

[Anon]

GD is kinda weak. ImageMagick is much better and the license is free.

The only trick is that it's not part of PHP itself, so you have to fork() a process which takes a performance hit.

Since images are likely going to be viewed again, I write code that:

1) Checks for a saved copy. If one is found, it's spit back out.
2) If not, generate the resampled image, save the result, then spit out the saved results.

In fact, I resize the images thru a function call (X/Y size parameters) and save the resized image with those values, so that I can call an image of any size and still cache the result. To keep things clean, A cron script deletes all resized files over 3 months old.

This gives a good combination of performance and flexibility.

-Ben