120 likes | 243 Views
File Size and File Formats. SIZE. DOES. MATTER. Digital cameras often save images in one of several formats:. JPG. BMP. TIFF. RAW. Others.
E N D
File Size and File Formats SIZE DOES MATTER
Digital cameras often save images in one of several formats: JPG BMP TIFF RAW Others Most of these are unsuitable for use on the web, and even JPGs (which are suitable) can be much too large or can have other issues that should be dealt with before putting them on the web. But, most image types that are unsuitable can be made suitable, using appropriate free software (available here in the lab and at home). There are also other sources for images, like the web itself, but just because it came from the web doesn’t mean it’s right for what you want to do. Be careful. So what’s a suitable image type? Glad you asked . . . .
Most of the images you want to use in your web pages will be in either JPG (pronounced jay-peg) or in GIF (usually pronounced giff) formats. There is also PNG, but this is less common. If you’re looking at any other image type, you should consider converting it before you do anything else with it. In general, JPGs are suitable for photos and other complex images with lots of different colors, while GIFs are suitable for simple images with few colors, large areas of single colors, or with transparent areas, or with animations. JPG images cannot have transparent areas or animations. JPGs for photos, GIFs for everything else. GIF –Only a few solid colors JPG –Photo, many complex colors
File Size and File Formats Smaller File = Better Smaller File = Quicker Download GIF JPG JPG
1 1 2 2 1 1 File Size and File Formats Smaller File = Better Smaller File = Quicker Download 3 KB 256 KB 85 BMP JPG
Bits and Bytes A bit is the smallest unit of data a computer can work with, a 1 or a 0. A byte is eight bits. File sizes are measured in bytes, because it’s important to know how big they are – how much room they’ll take up, how long they’ll take to download, how well they’ll print, etc. A smaller file size is better than a larger file size, but this usually means the quality of the image suffers. In general, the larger the image, the higher the quality – but the slower the download time, etc. A kilobyte is 1000 bytes (1 KB), and is usually fairly small by web standards. Most images for the web fall into the range of about 10 KB (kilobytes) to 80 KB -- total -- for the page. Anything larger than about 100 KB -- total – for the images on a page, and you should ask yourself if there’s a better way. There usually is. An image that needs 100 KB on disk, or 200 KB on disk, or even 1400 KB on disk, needs to be reduced (optimized) before use on a web page.
File Size and File Formats GIF 4 KB 45 KB BMP 11 8 KB JPG BMP 96 KB 12 20 KB 240 KB BMP JPG 12
File Size and File Formats 63 KB JPG JPG 616 KB 9
File Size and File Formats 54 KB JPG 1 54 KB JPG
File Size and File Formats JPG 237 KB 8 28 KB JPG
File Size and File Formats DO USE JPG (photos)* GIF (solid colors, or if transparency or animation is required) PNG (any) *JPGs can still containlarge amounts ofinformation if notproperly optimized CONVERT AS NEEDED DON’T USE BMP, WMF, TIF Other formats