Image Etiquette

 

Rik Nilsson

Abstract

In the opinion of some geeks, usage of the Internet (and possibly computers in general) should require a “PC driver’s license” that you get by proving some knowledge of its workings. You should at least be aware of the negative impact on the Internnet you make if you don't understand how to optimize images for the medium. If you routinely share or publish images on the Web, you should learn to use image optimization techniques to minimize your “footprint”. This tip discusses basic image characteristics you can tune, without sacrificing image quality, using various commercial or even free image manipulation software tools that sometimes come bundled with your camera or computer.

What is an image?

Images, in terms of PCs and the Web, are electronic picture files. These are what make Web pages look pretty. If it weren't for images, Web pages would look like they did prior to 1991 when the Web was invented: boring, text-only and like bad college term papers. Now along comes the web and digital photography, not to mention spam, and the whole internet comes to a screeching halt. The reason is simple to understand: Only so much water can flow through a pipe.

Is it possible to be “rude” unintentionally? Yes. One way is to email all your friends grossly over-sized pictures that show every pore in your nose. Or to put them on your web page so folks can take naps or watch basball (kinda the same thing...) and nobody else in the house can get to the Internet while they download.

Size Matters

When you take a picture with your new spectacularly over-developed 13 megapixel camera, it comes out B I G ! -- unless you first set the camera for web-optimized sizes. I mean, out-of-the-box, your camera will probably be set to give its maximum 2,000 pixel by 1,000 pixel or larger image. This is because, inexplicably, the camera manufacturer thinks you work for The National Archives and wants you to be thrilled with your purchase. If the viewer software you use to display it didn’t shrink it to fit your monitor, it might require a 21-inch monitor to see the whole thing. Then it looks like you got to the movie late and had to sit in the front row.

Giving someone a picture with too much information (too many pixels) for their system to display is not “green” in personal computing terms. Why? Because most people only have 15-inch or, more commonly now, 17-inch monitors set to either 800x600 or 1024x768 standard pixel resolutions. In addition to being at least twice too large for the monitor, that raw 2,000 by 1,000 image has three layers, one for each of the three basic colors red, blue and green which comes out to either 16 or 24 bits per pixel. So multiply: 2,000 x 1,000 x 16 = 32,000,000 or 32 million (mega) bytes (a byte is a computer “word” - 8 bits - one memory cell) or thereabouts, of information. Of course, your megapixel camera probably “compresses” that some, so it might come out as small as say, a puny 6 to 10 million bytes, if you’re lucky.

Even a compressed image that size could still take up to 10 to 15 minutes to travel over a typical phone line computer connection. Maybe even longer, what with all the “do-overs” your modem has to perform because of electronic noise from your neighbor’s lawnmower, TV, blender and microwave. Put many of those on your web page, and folks will run, not walk, to another page in a hurry. If you send one to someone in an email, the recipient will wonder why it takes so long to get their mail. If the email exceeds a threshold for size, their mail application or service might even cut it off early or refuse the message altogether.

Be Courteous

It is good internet etiquette (manners) to “optimize” your pictures before uploading them. Optimizing means choosing the right “footprint” for the medium (email, web, printing on paper or your photo-perfect printer). Read your camera’s manual to find out how to set it to take pictures for the web or email. That can save you time later, if the camera has such a feature, because you may not have to optimize at all. Read the manuals for the software that comes with the camera for ways to optimize, that might be better than the way I’ll describe below. The point is that, hey: we're targeting someone’s modest 72 or 96 pixel-per-inch video screen, not printing in the National Geographic, okay?

A good rule of thumb for email and web images is to keep them under 100Kb(kilobytes) in size, in terms of the size of the file. In terms of the apparent size of the picture as it is viewed, that's about 8 inches, or about 600 to 700 pixels. I prefer to target a standard size of 640 pixels. Most cameras these days come with some software to accomplish the optimization, and may even have “email” or “web” settings. Use them. Please. Especially if you intend to send them to me.

If you are just going to email your image, you can use Microsoft’s method.

New PCs come with at least WindowsXP Home version. Most new Macs come with OS X. Both of these operating systems (OS) contain programs to optimize picture sizes. On a Windows PC, the program is “Paint” and on a Mac its “GraphicConverter”. Linux OS users are inherently intelligent enough not to even have to read this article, let alone be told how to optimize, so I won't cover Linux. When they’re rude, it's on purpose. Anyway, they can use a Photoshop-like free application known as “The Gimp”.

Most cameras these days come with some minimum of software to upload the images from the camera to your computer either from the memory chip or with a cable. (I recommend using the cable, to minimize wear and tear on the camera components; cable plugs are designed to take many, many plugs and un-plugs -- camera chips aren’t.)

If you have a PC, get to know the software that was bundled with your camera, it may have tools to scale and optimize your images, along with instructions on how to use those features. Look for terms such as “optimize”, “quality”, “compression”, etc. You can usually choose a “quality” setting of 50 to 60 out of a scale of 0 to 100 without making a visible difference in image display on your monitor, while reducing the file size by over 70 percent! If no image manipulation software came with your camera, then you're stuck with what came with your computer unless you bought Adobe PhotoShop or downloaded some free software -- yes, there are loads of serviceable free image software tools out there, like “EvJO Photo-Image Resizer” which will quickly optimize single or multiple images and convert from TIFF to JPEG formats, for example. Google "free pc image manipulation software".

Optimizing On A PC Using “Paint”

(NOTE: This method only reduces the pixel size of the image. I know of no way to change JPEG compression ratio on out-of-the-box WindowsXP. You should learn to do that using the software that came with your camera. Find out how to alter the “quality” of JPEG images to “medium” or “low”. You might also try this freeware JPEG optimizer for small images: http://www.dirfile.com/interactive_jpeg_optimizer.htm)

Here’s a site where you can download a free image resizer application: http://www.evjosoft.com/PhImageResizer.html

  1. Get the picture from your camera to your PC, by following instructions in your camera's user guide.
  2. Put the picture somewhere you will readily be able to find it - for instance, "My Documents > My Pictures", or on your “Desktop”.
  3. Open your calculator and determine the amount of “shrinkage” you want to make.
    1. Divide the final width in pixels you want by the current width in pixels to get a percent reduction.
    2. For example, if the original size from the camera is 2048 X 1536, and your final size should be 125 pixels wide, divide 125 by 2048 to get .061035 or about 6%.
  4. Click “Start” and choose “Programs > Accessories > Paint”.
  5. When Paint starts up, select “File > Open” and find your picture. Click “Open”.
  6. Select “Image > Stretch/Skew”.
  7. Enter your calculated percentage into both the horizontal and vertical stretch number blanks, and click “OK”.
    (Note: If the shrunken image is too small, you can select “Edit > Undo” and use the selection tool to pick part of the image, copy and paste to a new image, then shrink as described before.)
  8. Choose “File > Save As...”, and give the picture a new name, such as blah, blah “smaller.jpg” or “myimage-th.jpg” or whatever seems appropriate. Make sure the new picture is going somewhere where you will remember where it is!
  9. Click “Save”.

Here

Optimizing On A Mac Using "GraphicConverter"

  1. Get the picture from your camera to your Mac, by following instructions in your camera’s user guide. (You can also use iPhoto when it launches automatically just by connecting your camera and turning it on... I love the Mac!)
  2. Put the picture somewhere you will readily be able to find it - like “Pictures”, or on your “Desktop”. Create a new folder first, if you wish.
  3. If you haven’t got GraphicConverter in your Dock, launch it from the Applications folder by double-clicking its icon.
  4. Select “File > Open...” and locate your picture in the Finder window that comes up. Select the image name and click “Open”.
  5. In the Picture menu, select “Size > Scale...”.
  6. Select units of “pixels”, set the size of the picture to 800 x 600 pixels or smaller, with “Keep proportions” and “Scale picture” selected. Click “Ok”.
  7. Choose “File > Save as...”, and give the picture a new name, like blah, blah “smaller.jpg” or whatever seems appropriate. Choose “JPEG” format from the pulldown menu. Make sure the new picture is going somewhere where you will remember where it is, like the Desktop. (Note: I suggest you further optimize by clicking “Options...” and setting the Quality to “medium” - between 30 and 60. Clicking “calculate file size” will show you the remarkable savings.)
  8. Click “Ok”, then “Save”.
© 2005 Rik Nilsson,
All rights reserved.
Richard H. Nilsson/Sept 23, 2005