Seeing is believing, the saying goes. That phrase dates back to the 17th century, but it means more now than ever. In our image-driven culture, we place value on what we can visualize at a glance.

That’s why tweets are 35 percent more likely to be re-tweeted, Facebook posts are 85 percent more likely to be “liked,” and whole websites are 90 percent more memorable when meaningful images or graphics are embedded in them. Regardless, we tend to treat all visual content the same way, no matter the source or purpose, and have since the dawn of the browser-based web 20 years ago.

The result is an abundance of images that appear blurry or ill-defined—images that appear too small or too large for the space allowed or that hinder a browser’s ability to display a site quickly and effectively.

We never learned—or if we did, we keep forgetting—that digital image formats vary, and each has a distinct, optimal purpose. Lacking an understanding of those purposes, we risk losing clicks, clients, and valuable attention.

So, let’s learn, remember, and properly use the three common image formats:

• .GIF It’s pronounced “jiff,” like the peanut butter, though some prefer “giff.” Either way, it stands for graphics interchange format, and it was developed by CompuServe in 1987 as a means of transferring space-hogging graphics files through slow connections. Animations, icons, line drawings, cartoons, and images with limited color palettes are better as GIFs because GIFs permit certain colors to appear as transparencies instead of real pixels and can combine pixels of two colors into one to further reduce file sizes without diminishing image quality.
• .JPEG (or .JPG) This one, pronounced “jay-peg,” stands for Joint Photographic Experts Group, and as the name implies, it was developed chiefly for photographs. Created in 1986 by the aforementioned group, JPEG is the standard file format programmed into most digital cameras, and it employs a complex algorithm to compress images for optimum web display. Some image quality is lost during this compression. However, in order to simplify compression, JPEG robs from subtler tones the human eye has difficulty noticing, yet it preserves the more distinct differences between light and dark.
• .PNG Pronounced “ping,” the format with the full name portable network graphics went to market in 1996 containing elements of both the GIF and JPEG formats. It was developed as an open-source substitute for GIF, and it is optimal for working with complex graphic logos and large photographs that do not need much compression. However, PNGs are relatively new, so PNG images may not display well, or at all, on older browsers.

Not all digital images are the same. Treating them as if they are leaves a bad impression with web audiences. By being mindful of these formats and their principle purposes, you can rest assured that the first visual impression you make will be a good one.