Pre-resize image to speed up page loading

It's obvious, that users upload images in a higher resolution, then actually is needed on a website and they needs to be resized.

Right now to speed up uploading process In-Portal don't resize image right after uploading, but only at time, when it's displayed in a different resolution on a website.
This seems to be very good solution when:

• small amount of users tries to view a page with image thumbnails displayed;
• images were originally uploaded in low resolution (smaller then 1MB on size).

But in case when a lot of users tries to see page with resized images at a same time and original images are ~4MB+ in size, then it will take a lot of memory and will attempt to resize same image multiple times.

In-Portal don't pre-resize images in background, because it can't guess what image dimensions would be requested in actual theme, user set's as primary.

But I have an idea, how to overcome that:

Create new column in Theme table, called ImageResizeRules, where per-path image resize rules will be written in following format:

• /system/path/one/:format1
• /system/path/two/:format2

Usually each line would look something like this:

/system/images/manufacturers/:resize:100x75;default:img/no_picture.gif

Actual data to place in ImageResizeRules field of the theme database table will be retrieved from <image_resize_rules> node in /_install/theme.xml file of individual theme.

Then CRON script would scan all rules from each theme and pre-resize images according to them.

Even more, if we would consider using Message Queuing servers, like ZeroMQ, then we could schedule resize jobs right after image was uploaded.