Icons for web

In 2012 I am worked for one printing company in London. I have been in charge of preparation files for print. Every day I checked about 60 incoming files and fix about 10 of them. I was surprised how many incoming artworks didn't have any bleed (extra area for trimming).
And I had to create 2-3 absolutely new design a day. I love being busy. The more tasks - the better. 
When i had a little bit more spare time i created assets for company's website.
Before it looked like this. I have began from icons. First icons I have created in Illustrator. They were vector icons with gradient. I wanted to select colour for them later. I saved each icon separately as a png-file with transparency.

Then I had to create icons for every kind of our productions. In order it will be possible in future to replace previous icons to new ones i used their file names. It looked like a product_image211.png, a product_image312.png, a product_image789.png... and so on. In fact, I didn't have a direct access to webserver. I just saved web pages to my HD and I assume, all names of  icons were produced by webserver.

Our director who was responsible for updating of corporate website asked me to separate and to rename all files for each kind of our production separately. They asked me to make different size of icons for different sizes of our production (A3, A4, A5, A6, A7 - icons should be smaller depending of paper size). It was more than 250 icons.