For those of you who may have questions about preparing photos for emailing as attachments or posting to forums, i might be able to help a little. o ften run across examples of HGE files and on occasion, requests for information. here's my modest attempt.

the standard file format for sending photos or posting is called JPEG, or JPG. JPEG is a file format. it is an acronym for Joint Photographic Experts Group which created the file standard. JPEG compresses the file size of a digitized photograph. for a general example, imagine 3 pixels or units of the color red, perhaps seen in someone’s shirt within the photo. JPEG, as it was described to me years ago, might look at that and determine the middle pixel of red is unnecessary and exclude that, pushing the outer two pixels of red together. This is called a "lossy" form of compression meaning of course, there is a loss of information in the procedure. It is a method designed to balance file size with file quality as judged by the human eye.

the amount of compression is variable. you control this usually within a program called an image editing program or software. a common one used in professional industries like publication is produced by a company called adobe and the software is called Photoshop. this is what i use so i’m familiar with it but other software should allow for similar adjustments. there are several image editing software/applications available, many much much cheaper than Photoshop (the full version runs about $600 i think). these alternatives are sometimes available as shareware (small fee) and downloadable from the internet. Image editing software, sometimes a stripped down version of Photoshop, used to be bundled for fee with peripherals people purchased for their computers. for instance printers used to come with CDs which had extra software. i imagine they still do.

Among other things, image editing software allows you to crop a photo and reduce it’s pixel settings. most computer monitors, which of course are used to view web pages and email, have a resolution of 72 pixels per inch. photos may have ppi settings of 100, 150, 200, even more, depending on how your camera captured them in the first place. if a computer monitor only sees 72 ppi, anything more than that is typically just unused and means a bigger file size overall and, as in my own personal case, slow loading or downloading on a standard 56k modem. it helps people like me to see photos quickly and efficiently if they were knocked down to 72 ppi. we’re talking possibilities of 20:1 ratios.

I use a 17 inch CRT monitor, not one of the new flat screen models. still, i find that cropping the image, or resizing it overall to something smaller helps as well as compression through JPEG. personally, i find that many cameras will capture a photo that can measure 20 inches across. if you only knocked down the ppi size to 72, it would still view as 20 inches across. the next step is to resize the photo. as an example i find that horizontal photos can be fine if you knock it down to a 7 inch size horizontally. the vertical size can be/should be resized automatically to fit the original proportion. it may take some reading of a manual to realize how to do this.

In Photoshop, and i imagine other programs (Paint Shop Pro was often lauded by people who were using the PC platform) you are offered the opportunity to save a photograph in various formats, one being JPEG. TIFF, PICT, and GIF are other well known file formats but they were not designed for photographs. choose this. name your file without spaces or special characters. numbers and letters are generally fine and will not cause problems for others.

after you name the file and click save, you are prompted to set a compression setting or ratio. in my Photoshop, version 7, there is a sliding scale of 1 through 12, 1 being the MOST compression,12 being the least. i typically save at a setting of 4 or 5. this allows for a relatively large amount of compression but the quality is still nice and you cannot see any degrading of quality. unless of course the original photo was somewhat lacking in the first place. ;-)

resizing of a digitized photo AND adding JPEG compression can often times reduce a 1 or 2 megabyte photograph (1,000-2,000k) to something like 100k, much more if you’re dealing with black and white photos. i usually try to get between 60k-100k.

there is a bad result if you compress and save as a JPEG, then save it again AS A JPEG which is called “JPEG artifacting” and this can be seen as pixelation of a photo, readily apparent in wide swaths of color, like skies. so when you save as a JPEG, do it only once. if you’re curious, save an original untouched copy of a photograph (for instance, saved in TIFF file format), compare that to a COPY of that original saved as a JPEG, and compare those two to another copy of a JPEG, saved one or two more times as a JPEG again. you’ll see the artifacting. it can get ugly.

Correctly reducing the size of a digitized photograph and saving with JPEG compression simply creates smaller file sizes without loss of DISCERNIBLE quality which helps save on storage space, eases sending file sizes via email attachment and speeds up web page loading for the viewer. this is less of an issue for people who have fast internet connections like broadband or cable modems and the like, but many are still connecting with old fashioned modems.

One more thing i’d like to add. if your intended use includes printing, either by an internet photo company’s services or your own ink jet printer, always work from a digitized photograph that does NOT have significant JPEG compression. it’s actually best to save one uncompressed copy of a photograph, which can also be backed up on a CD, to help enhance printer quality. printers, which are measured in Dots Per Inch (dpi) can reproduce much higher quality than the 72 ppi ratings of most monitors.

I hope this helps at least one person out there. i probably should have saved this explanation until after i’ve had some sleep. If anyone has any questions i’d be glad to try to clarify. and if i’ve made any horrendous mistakes or wishes to add to it, please contribute.

eric
fresno, ca.

Thanks for the excellent information. JPEG format photos, properly sized for use in emails and on the web, do a lot to ensure quick page loading and smaller file sizes in email boxes.

I will add that there are some situations where JPEG files are not so good - most of these fall outside the internet or email use, however. JPEG files cannot be edited without losing some degree of quality each time you edit the image. Therefore, if you intend to use your photos for more than just internet or email use, you're better off taking large JPEG shots and then saving them as TIFF images on your computer before doing any editing work. From there, you can resave any edited image as JPEG in a size and scale proper for web use and still retain the TIFF image for other revisions or uses.

Most better digital cameras can take photos in RAW format files, but these require special software to "develop" them before they can be used for anything. They are the superior means for taking digital images, but they are not at all required for what most people do with their digital images - internet and email use.

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In a smaller nutshell, use Irfanview. It resizes, it is able to display many file formats, even text, and best of all it is free. What Eric sez about having pictures developed from uncompressed jpg files. Many (if not all) digital cameras save their pictures in jpg format with additional meta-data information. Much of this is stripped when a jpg is compressed, and while it may not make much a difference to the naked eye when view the file on a pc monitor, it will make a difference when you print it.

For more info you can go here: [download.java.net]

Lou

Very good, Eric. Thanks! I would like to add that (having done this type of work for many years) Tom makes an excellent point. If you are into digital photography and graphics work, convert/save your work in TIFF format to edit/play with then re save as jpg, keeping the Tiff file for future work. As an owner of both Photoshop ($600) and Paintshop Pro ($99), I will say that I almost exclusively use Paintshop Pro. IMO, PSP is as good and will accept the Photo shop plug ins.. High megapixel cameras produce very large pictures/files which need to be resized before they are practical for internet/e-mail use. If that's what you use your digital for, I would highly recommend that you reset your camera setting to around 2 megapixels max.

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!

I should mention that PhotoShop Elements is a pretty darn good program for those who don't need the power of regular PhotoShop. It has more features than most would ever use, including a "save for web" auto command that will automatically scale and size photos in JPEG format for web use. It also has a RAW image converter. It sells for about $100.

And, most cameras can do well on their own if you set the image quality to LOW - this produces a JPEG file in the size and type resolution that is nearly perfect for the web or email.

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If you want a wonderful photo program, download Picasa from google...it does a lot of things...and the price is right....it's free

[picasa.google.ca]