which method is faster to increase page speed by re sizing remote PNG images in php.?
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Introduction: My Webpage shows the remote server PNG images of Size 90 by 90. I want to re-size it to 50 by 50. There are 300 of images on single webpage which make it slow. Normally My Webpage daily opens by 2k users.

By Searching a Lot I Found these methods but I don't Know Which is Better Please help..
Here Are My Approaches:

1. On The Fly.
2. re-size and Save it to database.
3. re-size and save it to my web directory.


I am using mysql to fetch rows each row has name, 'url to image', id , time, description. This 'url to image' is my problem.
I think Saving to MYSQL Database is good which make retrieving from it easier and maybe faster than others.

Please provide me any idea of coding where to start. I am Trying this image re-sizing for first time.. 

Thank You