Hand-drawn era：

• PuTTY itself (1999)：32×32 pixel icon using a limited palette. Two computers under a CRT monitor with a floppy drive and a yellow lightning bolt suggesting electrical communication. Blue screens for on status. No specific reason for the design choices.
• PSCP (1999)：An icon based on the PuTTY icon with one computer replaced by a paper with variable-length lines suggesting a written document and a lightning bolt. Later reused for PSFTP.
• Pageant (next)：Originally intended to be a secret agent icon but ended up with a hat on a larger version of the PuTTY computer. Had to draw a 16×16 icon for the System Tray with antialiasing tricks.
• PuTTYgen (after)：An "computer + lightning bolt + key" icon with a weak visual pun. Lightning bolt was inaccurate as PuTTYgen doesn't do network communication.
• Configuration dialog box：An icon with a spanner overlay on the PuTTY icon to represent configuration. Also included a monochrome version.

Scripted era (2007)：Displays became bigger and Windows defaulted to 48×48 icons. Wrote a script to auto-generate icons for all tools, ensuring all versions (48×48, 32×32, 16×16) and black-and-white versions. There are some differences between original and scripted icons, like the Pageant icon size.

• pterm (2002)：Ported PuTTY code to Linux and wrote an X11 terminal emulator. Drawn an icon with just one copy of the computer logo and a separate icon for the configuration dialog. Later used for Windows pterm in 2021.
• Installer：Used the flexible icon-drawing script to support true colour icons. Drew a cardboard box with a lightning bolt for the installer icon and used 16-colour mixes to support older systems.