Bijou is a set of beautiful icons that are tiny-in-size yet pixel-perfect in details.
There are 120+ items in the set which consists of popular icons like charts, actions, arrows, smileys, etc.
The download package includes transparent PNGs, a PSD file with all the icons as layers and a Photoshop custom shapes version (.CSH).
Also, usage is free for personal and commercial projects (no attribution required).
Smashing Magazine has recently shared a very nice set of free vector icons named August Interactive Icon Pack.
The set is focused on web UI design and includes items like arrows, actions, media player, download icons and more to ease creating such interfaces.
They are designed with Adobe Fireworks and exported as an editable + layered Photoshop file.
Download package consists of the PSD file, Fireworks PNG file and transparent PNGs for each icon.
PremiumPixels, a website by Orman Clark that regularly releases design freebies, has recently published a very nice set of icons.
The set is named Pixicus and it consists of 106 pixel-perfect icons that are mono colored.
There are 106 icons with items like actions, social networks, users or devices and they are in transparent PNG format with 12*12px sizes.
Desktop users are experienced enough to know how they can interact with a website, use shortcuts and get the most out of the browser.
For touch-enabled interfaces, things are different. There is a new question: "which gestures are supported by the app/website?".
Cue is a free (public domain) gestural icon system that aims to build a standard visual language of touch-based interactions.
There are icons for actions like swipe, drap, touch, tap and hold, spread and more.
Each icon comes in a labeled and unlabeled version and the set is in .PNG, .SVG Omnigraffle Stencil and InDesign formats.
Icons 8 is a regularly updated set of beautiful icons that are inspired from the Windows 8 interface.
Currently, there are 140+ items where 3 new ones are added each day (users can send suggestions for new icons).
They are in transparent .PNG format with 26*26px size and come in black&white colors.
There are icons of arrows, e-commerce, payment methods, sports, music and more.
Update (14 Feb 2012): The icons are now also available in .EPS vector format.
MimiGlyphs is a beautiful set of free vector icons with 80 slick items in the pack.
The set is in .PSD, .CSH (Photoshop custom shape) and transparent PNG formats (16*16px).
Items in the set are a good fit to be used in web apps considering there are icons of actions, charts, comments, devices, social networking and more.
And, they are free to be used in both personal and commercial projects.
Iconshock has released an exciting set of icons named: "Shock iPhone Icons" today.
The set includes 600 unique items that are designed to meet the requirements of the iPhone iOS guidelines.
Items inside are the ones that can be used by most of the mobile and web apps (like actions, devices, filetypes, smileys, etc.
They are in transparent .PNG, have 2 sizes: 30*30px + 40*40px and bundled with ~4,400 variations of each size.
They are free to use in both personal and commercial (requires attribution) projects.
P.S. They also have a similar Android icons set.
Using transparent images in websites make so much sense in many cases as they fit perfectly to any background.
However, there is sometimes a big empty space around images which can create confusion when clicking on them as users may not easily realize that the clicked part of the website is actually an image.
alphaPun.ch changes that by tracing the opaque part of PNG or GIF images and then punch through the alpha channel so the stuff behind it can be clicked.
Behind the scenes, it creates a mask for the opaque part of images along with masks for the clickable content behind them. The masks are positioned above the real image and users will actually be clicking to these masks.
It works by drag 'n' dropping an image to the loader and an HTML-CSS-JS (with jQuery) code is created automatically.
The project is definitely not a good fit for every image on websites but there will certainly be good cases of use.
P.S. alphaPun.ch is open source.
The increasing variety and usage of device/screen types (cell phone, smart phone, tablet, desktop..) urge the need for serving web content accordingly.
Adaptive Images is a solution for delivering browser-size-specific images for any device.. automatically.
Adaptive Images is a plug 'n' play resource which can be easily integrated into any PHP website.
There is a built-in caching system for minimizing each image only once for each size.
Also, several options for customization exist including "array of browser-image sizes", .JPG quality and more.
Requirements: PHP 5+ with GD lib enabed
WebDesignShock has recently released a high-quality set of interface icons that follow the style of the ones used in Google+.
There are 204 items in the set, they have gray and colored versions (great for hover effect) and come in 2 sizes: 18*18px and 128*128px.
That's not all, besides .PNG, the icons are also available in .PSD format.
It has almost every item that a web application can need from actions to charts or devices. Simply, a must-bookmark.