The easiest way to demonstrate variable transparency is through an example. Using variable transparency, we can actually use transparencies as a gradient. The PNG file format is capable of saving variable levels of transparency. We can change the color of the ring, but this means we must know ahead of time what color background we are going to be using. There will always be a colored ring around the image. This is because GIF images can only use 1-color transparency. Notice the white ring around the image though. Using a GIF image with a transparent background allowed us to put our image on a different color background. The GIF give us a transparent background. Here's our background color we're saving the logo on. We want our logo to sit on a light green background color. This has to be an image file because we're using fancy type and also a graphic of an apple in place of the a. Let's use the Good Food logo as an example. This basically means that you can save your image with a transparent background. GIF images (and also PNG) support 1-color transparency.
If you need any level of transparency in your image, you must use either a GIF or a PNG. The GIF and PNG formats also both support transparency. Common examples of these types of images are logos, logotypes, and illustrations without gradients. The GIF and PNG image formats are ideal for images with flat colors (no gradients) and hard edges. File size for GIF and PNG images is generally related to the number of colors used. They store a minimized color palette in the image file and keys to where those colors should be located in the image. The GIF and PNG image formats use what is called "index-color". A larger pixel size will always result in a larger file size.Įxamples of images that should be saved in the JPG format: File size is directly related to the actual size (in pixels) of the image. When saving images in the JPG format, you can choose the level of compression to balance the file size and image quality. If transparency is needed in the background of your image, you must choose a different format. The JPG format is not capable of saving any transparencies. Think of a JPG as a highly compressed photograph. The JPG format does a very good job of compressing images with lots of colors and gradations in colors. The JPG image format was designed to efficiently store and compress realistic images and artwork (both in color and greyscale). Each of these file formats are designed with a specific purpose in mind, so it is important to understand the differences when we use them in our websites. There are three file formats for graphics used on the web: JPG, GIF, and PNG. This is especially important when using background images. Make sure there is sufficient contrast when using text in graphics so they are legible.Make graphics accessible with alternate text.This diminishes search engine indexing, accessibility, etc. Graphics should never be used for text content, except if a header necessitates including a logo.Avoid annoying images, animations, gratuitous effects - they get old fast without purpose.Graphics should help focus visitor’s attention on what’s important on the page.Large (file size) graphics add load time to a page - avoid.Web graphics should fit in with the purpose, organization and style of the site.
Our sites are usually quite boring without the use of graphics.
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