Sending images and graphic files across the Internet - how to get it right.

Holy jumpin' JPEGs Batman!

Anyone who has tried to get or send images has faced this dilemma.

What file type is best?

What's the difference anyway? Tiff, Gif, Biff! who cares?

Truth is, there is a world of difference in the various file types and no quicker way to send an editor into a psychotic fury than give him or her the wrong one on deadline.

Here's a quick-and-dirty rundown of the most common image file types and where it's best to use them.

JPEG

This clever image show a progressive
scale of compression from L>R

Named after the Joint Photographic Experts Group who created this standard of photographic computer file which first appeared on computers back in the early '90s.

It's really clever because when you create the file (either in the camera or with computer software) you can specify how much compression (quality) you think you need. On a scale of 1-100, 100 being virtually no compression and super quality.

JPEGs (.jpg or .jpeg) files travel really well over email and file transfer. You can have really big images (in pixel dimensions) travel in fairly lightweight files, so if you are sending images with your press release or story, JPEGs are by far the preferred standard.

Compression requires compromise, meaning that you are trading some level of image quality for economy. You can get away with lesser quality for screen (online) publication than print, but with the new High Definition LCD screens in devices like iPads, this gap is closing.

The whizbang software compresses areas of like colour or tone. So, an image of one solid colour will compress to almost nothing, while one with lots of fine detail will not compress as readily. This is why comparing file size (in kBs or MBs) to image size (in pixels) can be confusing.

TIFF

The Tagged Image File Format (.tif or .tiff) is a useful file still preferred by graphic artists and designers using Adobe products for desktop publishing. It can store lots of different types of data besides just the image.

As a rule-of-thumb, unless you know you are sending your image or graphic to an experienced graphic designer or layout artist, a TIFF is overkill and likely to frustrate a regular publisher, especially an online publisher or blogger as TIFFs cannot be displayed on many common browsers.

PNG

A PNG image

The Portable Network Graphics file is a newer file format designed mainly to replace the clumsy old GIF that has been around since 1987.

Although PNG can be used reasonably well with images, it is better suited to net graphics and digital art. 

Logos, for example, come up well with PNG because you don't get those blurry 'jaggies' that can appear when JPEGs get passed around a lot - and your corporate colours are more accurate.

GIF

Closeup of JPG (L) and GIF (R)
click to enlarge

The Graphics Interchange Format is older type of image and graphic file now largely redundant and superseded by more useful and efficient types, like PNG. While it still has some uses, like basic animation, there is almost no need for this file type anymore as the image quality is poor.

PDF

The Portable Document Format is just that, a format for documents.

The most common and appropriate use for this file type is for the distribution of printed information like ... documents. It's clever because you can embed fonts and graphics and when passed around and around on the Internet, the layout always stays the same (when set up correctly in the first place).

Public relations folks like to include PDFs as press releases so they and their clients can see how neat and pretty it is, but many journalists dislike this format because if they are cut-and-pasting quotes or portions of the information, it can be difficult to work with.

While it is possible to send images as PDFs - and some people do - it is likely to cause frustration to the receiver as they need to extract and convert the image to use it and more often then not, they will mess this process up and get really cranky.

Others

There are many other file types used for online purposes, but their application is specialised and limited. Unless you have a very good reason, you can ignore and avoid these ones for online purposes.

BMP - Bitmap files

RAW - These come with lots of file extensions like .crw .cr2 .ari

EPS - Encapsulated PostScript

PICT - Classic Macintosh QuickDraw file

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Roderick Eime has been working with computer graphics and imaging for more than 20 years. He taught photojournalism at Charles Sturt University in the early '90s when digital photography and the World Wide Web were in their infancy.

He is now an award-winning travel writer and photographer.

www.travography.com