If you’ve played around with optimizing your website for small screens, you know one of the big headaches is resizing images. You can set the viewport in your head tags to make sure your main content is the focus on mobile devices, but you can’t easily shrink images.
On many mobile devices, rendering the images is what slows down page load times. That’s where TinySrc comes in. It’s a clever service that parses your images and presents scaled-down versions to mobile devices.
Using tinySrc is pretty simple, all you need to do is prefix your image URLs with the tinySrc domain, something like:
TinySrc will then detect the device that’s visiting your site (tinySrc has partnered with Device Atlas so its device listings are extensive) and serve out an appropriately shrunken version of your image.
If you’d like complete control over the size of your images, you can specify parameters in the URL. For more details on all of tinySrc’s settings see the documentation.
While you are relying on a third party service — a choice which always carries the usual concerns about speed and reliability — tinySrc is definitely one of the fastest, easiest ways to shrink your images for the small screen.
Producing images for the web invariably means minimizing the number of colors (and therefore the file size), and the index color system is another step in this squishing process. With a 216-color palette loaded, Photoshop will map an image to those colors when you move it into index color mode. While this helps the compression and allows you to choose bit depth, it also makes the colors dither, or shift numerically, to the palette. One way to compensate for dithering in the index mode is to use a histogram, which is basically a bar graph of each color’s frequency in the image. In most image-processing programs, you can manipulate the histogram and determine how much weight to give certain colors in the resulting palette.
If a computer-displayed image is interlaced, then it is rendered in alternating horizontal lines.
For example, browsers display interlaced GIFs in alternating passes, skipping every other line and rendering a kind of blurry image first and then sharpening it on subsequent passes. This is useful if you’d like your viewers to get a general idea of the image while they are downloading it. Interlacing for GIFs was designed to make bigger images quicker to download, but the problem is that an interlaced GIF actually has a larger file size than a non-interlaced GIF, so use this method cautiously.
If you’re at all interested in e-biz, you’d better get serious about tracking webographics. A user’s webographic profile includes platform (Mac, Unix, or Windows), browser make (IE, Netscape) and model (3.0, 4.0), and connection speed (T1, 28.8, 14.4). Each of these factors can have a dramatic effect on a user’s experience, and every developer must decide whether to build a site that’s accessible to everyone (meaning fancy cutting-edge doodads are out) or create something really cool that won’t work unless users upgrade. We, of course, recommend the former.