MIME-Based Transformations - Mastering phpMyAdmin 2.8 for Effective MySQL Management - page 229

Examples of Transformations
We will now discuss a few transformation examples. We will start by changing the
field type of our cover_photo field.
Clickable Thumbnail (.jpeg or .png)
We change our cover_photo field type from BLOB to MEDIUMBLOB to
ensure that we can upload photographs that are bigger than 65 KB to it. We then
enter the following attributes:
Here, the options are presented as width,height . If we omit the options, the default
values are 100,100 . The thumbnail generation code preserves the original aspect
ratio of the image, so the values entered are the maximum width and height of the
generated image. We then upload a .jpeg file in a cell (using instructions from
Chapter 6). As a result, we get the following in Browse mode for this table:
This thumbnail can be clicked to reveal the full-size photograph.
The thumbnail is not stored anywhere in MySQL, but
generated each time we go into Browse mode for this set
of rows. On a Pentium-III 500 MHz server, we commonly
experience a generation time of 0.5 to 1 second per image.
For a .png file, we have to use image/png as the MIME type, and image/png: inline
as the transformation.