Graphic design and web
design are two distinct visual fields that have different requirements, best
practices and methodologies.
For example, it’s much
easier in web design to use pixel-based/raster-based file formats (like JPG,
GIF or PNG). Conversely, vector files such as EPS and AI — which are scalable
without leading to pixelation — are better suited for graphic design, for things
like logos that might be used in a variety of sizes. As of yet, vector-based
graphics designed for the web (such as SVG or HTML5 Canvas) are not universally
and uniformly supported in all browsers.
In addition, graphics
meant for web use have certain best practices associated with them. One of
these best practices is that you should be conscious of file weight because you
want your web pages to be as fast as possible. As a web designer, you have to
try to reduce the amount of HTTP requests done by your graphics — whether
through lowering the amount of images you use or combining some of them into a
CSS sprite — as well as make sure you pick the right image format that strikes
a perfect balance between file size and image quality.
Photoshop is an industry-standard
tool used by both graphic designers and web designers. What follows are some
simple tips to follow as you create graphics meant for use on websites.
1. Save Your Graphics
with the "Save for Web & Devices" Command
In web design, you have
to make sure that your images are as small in file size as possible. But it’s
more than that — your images need to look good as well.
The perfect approach to
creating graphics in Photoshop is by balancing image quality and file size.
A common mistake that
web designers make is using the Save as command instead of the Save for Web
& Devices command in Photoshop.
The Save for Web &
Devices command creates files optimized for web design, in terms of image
quality, image resolution, browser compatibility and file size.
The command
additionally has a dialog window that you can use to fine-tune your images.
While you tweak the settings of your graphic, it will show you its effects on
file size and image quality.
In comparison, the Save
as dialog window doesn’t have as many options and often creates images that are
larger in terms of file size.
Below is a comparison
of the same image saved using the Save for Web & Devices command and the
Save as command. Notice that the file size difference is significant.
2. Consider Using
Web-safe Colors
Web-safe colors will
display correctly in most browsers and on most monitors, ensuring your website
looks the same no matter where it’s viewed.
The two easiest ways to
guarantee that the colors you use are web-safe are as follows.
"Only Web
Colors" Option
In the Color Picker
dialog window, check the "Only Web Colors" option located at the
bottom-left corner. This will limit the colors being displayed in the window to
just web-safe colors.
Convert a Color to a
Web-safe Color
Convert any color into
the closest web-safe color by clicking on the little cube in the Color Picker
(next to the "Current" and "New" color boxes).
3. Consider Using the
"Progressive Scan" Option for JPG
The JPG file format is
ideal for photographic and high-resolution images. Depending on your projected
audience, a progressive scan JPG can be the way to go, as the image will
gradually render as the site loads (though on modern broadband Internet
connections, this type of wait time is rarely an issue). This allows the user
the ability to quickly see the image before it fully downloads, making the web
page feel more responsive.
For a more extensive
guide on the subject, read JPEG 101: A Crash Course Guide on JPEG.
4. Save Graphics with
Transparency as PNGs
The PNG image format is
great for images that need to be rendered with transparency.
PNG transparency is
supported in most mainstream browsers but watch out if you find yourself having
to cater to IE6: parts of your PNG that are meant to be transparent will show
up gray. There are workarounds to avoid this issue (e.g., IE PNG Fix JavaScript
library) but they can be a hassle to implement.
For more information on
PNGs, read the Web Designer’s Guide to PNG Image Format.
5. Save Animated
Graphics as GIFs
While there is an
extension of the PNG image format called APNG (which stands for Animated
Portable Network Graphics), it lacks browser support.
If you’re choosing
between PNG and GIF, it’s usually a good idea choose PNG unless the image is to
be animated.
6. Pay Attention to the
"Download Time" Information
It’s vital to make sure
that a site loads quickly and looks good, which is why saving and optimizing
your graphics is important. Below, see what a simple change in a file-saving
option can do to an image’s file size.
JPEG at Maximum Quality
JPEG at Low Quality
A good practice to
follow is to lower the quality until you visibly notice degradation in image
quality.
When you’re optimizing
your images, always pay attention to the Download Time, which is displayed on
the lower-left corner of the Save for Web & Devices dialog window. Below,
you can see that the image being saved will take approximately 2 seconds to
download on a DSL Internet connection at its current settings.
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