When designing a website, it’s important to make sure that the size of images are relative to the dimensions of the screen being used; doing so can mean that websites load faster, while also cutting down problems with resolution and images loading in too large a format for users. To make these jumps in filesize relative to different screen dimensions, it’s important to consider the resolution and pixel density for individual images, as well as how reducing image size and using CSS media queries can help you with your custom website development.
Loading pages with images that haven’t been optimized can cause problems if the size given for an image isn’t suitable for the size of the screen being used. If there are no maximum heights or widths set within the code for a site, pages can end up with images that are either too slow to load, or that end up being stretched across a page. In this context, it’s important to pay attention to image size specifications, and ways for enabling different browsers and devices to recognize what size an image should be.
The first approach you can take to ensure that an image is the right size and resolution for average screen sizes is to edit down larger formats in picture editors such as Photoshop and other applications. Having an optimized image means that a page will load faster; you can also choose to add attributes to an image that will preserve aspect ratios when resized, which will prevent distortion and enables your site to look proportionate.
Selecting the right image format for different screen sizes and dimensions is also important. Gif files made up of grids of pixels are among the most common options that you can take, as are .jpegs, which are more common for photographs and images with a lot of colors. You can also .png files that can handle larger amounts of color, while still being compressible. When adding images to your website, you can set basic and alternative size types for browsers to recommend, which can enable different amounts of space to be allocated on a screen.
Some internet browsers will automatically resize an image to the size of the screen being used, but will compress some images, with a risk existing for distortion. The automatic resizing of photos on the side of an external server means that you lose control over specifying exactly how you want an image to appear on your site, and can result in a loss of resolution when viewed live.
Another approach that you can take to resizing image files for different screen sizes involves using media queries in CSS and aspects of responsive design; in this context, media queries will resize parts of a page to meet the demands of different media and screen sizes, with maximum heights and widths set. As a result, browsers should be able to recognize when a page is being viewed on a particular screen.
Background images for websites can also be set with specific sizes and pixel ratios that will reproduce the same effects across different devices. For foreground images, it can also be possible to use Scalable Vector Graphics when programming a page and setting up its attributes. SVG is a particularly useful approach to take, as it will convert graphics in an XML format, allowing for zooming and resizing without a substantial loss of quality.
Adding in this flexibility for images on different screens means that browsers don’t have to work as hard to load pages that have particularly large images, reducing the bandwidth that you need to use; doing so means that you’re more likely to have a smooth user experience, and that you can make your website appear consistent on a wider range of different devices.
Photo Credit: Flickr/Jayel Aheram