Lesson #2 -- File Sizes

In Lesson #1 I said the picture size is unimportant. That's true. The picture size is not important if all you want is a great picture. However, when you want to send the picture in an email attachment or post it on your Facebook page, size can make a difference. I keep all my digital photos in dated folders in their original large size just like they came from the camera.

In 2002, my first old 1.2MP (1.2 megapixel) digital camera took picture dimensions of 800 X 600 pixels with a filesize about 160 KB.
Since 2007, Linda's 8MP DSLR (digital single lens reflex) has been set to dimensions of 3504 X 2336 pixels and filesize about 3.5 MB.
More recently, my Kodak 9MP snapshot takes pictures with dimensions of 3472 X 2604 pixels and filesize is about 1.5 MB.

You can change these settings inside your camera using the camera's menu under "Picture Size." Keep it on the largest setting (default) unless you need smaller pictures. The largest setting will capture the most detail. To equal the quality of the best old film cameras you need at least 10MP, a large CMOS chip (camera electronics), and a great lens.

Mostly, you don't have to worry about the picture size until your computer disk fills up and you have no way to make backups. I've talked to many friends who don't even have a way of transferring their pictures to their computer. I've also talked to many who took dozens of pictures then lost them when their computer disk crashed. I'll mention how to do backups at the bottom of this page.

Sometimes you need to take a smaller picture. There are several ways to make a picture smaller with various photo editors or email tools. The quickest way is to set your camera to take smaller pictures to begin with. See Picture Settings of your camera's user manual. The best way is to take the largest picture possible then make a smaller copy of it using a photo editor or email tool like the one included in Windows Live Mail.

My snapshot camera, a Kodak Easyshare C160, can take the picture sizes below.

I've created a table to explain the values of a digital picture that can be adusted in the camera or edited in software. First look at the glossary of terms below then check out the table underneath.

MP (Pixel Resolution)
Notice the selection in RED highlighted in the above photo of my snapshot camera. It says the camera has selected a pixel resolution of 9.0 MP to take photos in a 4 to 3 ratio. This means the full width and height (all 9 Megapixels) of the image sensor (CCD or CMOS) inside the camera will be used to capture the next photo you take.

Aspect Ratio
The 3rd column in the table below lists the Aspect Ratio, 4 by 3. The first number is the width followed by the height. In a 4:3 Aspect Ratio, it means the height is 75% or 3/4 the width. Here are the 3 most common aspect ratios used: 3:2 = same as 35mm film; 4:3 = same as your old TV set; 16:9 = same as your new HDTV. In print, think of it this way. Remember how you have to either mat or trim an 8 X 10 or 8 1/2 X 11 photo to fit an 8 1/2 X 11 frame? Many of us remember getting the scissors out to make our pictures fit the photo album or frame we use to display it.

Actual File Size
This is the amount of space the picture will acutally take on your computer's hard drive, as an email attachment, etc.

Dimensions
This determines the Pixel Resolution or how "big" a photo your camera can take. If your camera can only take pictures that are 1280 by 960 pixels that's 1,280 times 960 = 1,228,800 pixels (One point 2 million). Stated another way, that's 1.2 MP. Today we think of that as a "rating" system for our camera. We think an 8MP camera is somehow "better" than a 6MP camera. Yes, the 8MP will capture more detail but like a paint job on a vehicle, the detail may still be poor quality. Quality comes not from the size but from the lens and size of the camera's image sensor. With better lenses and chips, a larger file size can be good.

NOTE: In the table, click the photo. Another window will appear. The photo you clicked will be circled in red. Click again on the circled photo to see it's actual size on your computer. In some web browsers a + (plus) sign will appear. This means your browser has reduced the viewable size to get all the picture within the frame. Click again to see the actual size. With the largest photos below you should see a giant banana on your screen.

CLICK the photo	Pixel Resolution	Aspect Ratio	Actual File Size	Dimensions in Pixels
	1.2 MP	4.3	354 KB	1280 X 960
	2.1 MP	16:9	522 KB	1920 X 1080
	2.2 MP	3:2	484 KB	1800 X 1200
	3.1 MP	4:3	632 KB	2048 X 1536
	5.0 MP	4:3	1.09 MB	2592 X 1944
	6.8 MP	16:9	1.27 MB	3472 X 1952
	8.0 MP	3:2	1.48 MB	3472 X 2314
	9.0 MP	4:3	1.70 MB	3472 X 2604

Another Example
A word about density and "actual" size. Here are two indentical photos. I edited the one on the left so that the "actual" (print) size is 3 inches by 4 inches but density is only 72 pixels per inch. Your web browser will adjust the viewable size based on your computer monitor's settings. The "actual" size of the photo on the right is only 1 inch by 1 inch but the density is 400 pixels per inch, 4 times the pixel density of the photo on the left.

Because of the higher density, your computer monitor's settings will expand the photo on the right to appear much larger. That fools a lot of people. That's why sometimes when you print a web page you expect the printed copy to look like the screen. It doesn't. Sometimes your one screen you're looking at prints out as 10 chopped up pages because a printer interprets the "actual" size rather than the pixel density.

Backups
Now, just a brief word about preserving your digital photo files. This may surprise you but, according to archivists, there is no permanent or long lasting safe way to preserve digital information. The reason is because of advancing technology. Just look at the history of audio files.

Today you can play music from the internet, your computer's hard drive, flash drives, portable drives, and various portable music players including MP3 players, tablets, and cell phones.

In the past, we've used (and still use in some cases), CDs, cassette tape, and various size phonograph records.

45 rpm & 78 rpm records, 8-track tape, and reel-to-reel magnetic tape are rarely seen these days.

Whether or not you know these technologies, recordings have been made on 5/16" thick 78 rpm records, cylinders, and magnetic wire recorders, among other obscure devices no longer used.

To hear some of these recordings you would first have to locate a device to play them. Digital photographs have the similar problems. As technology advances, your digital photos may become unviewable. THE BEST WAY TO PRESERVE YOUR PHOTOS IS STILL THE SAME -- PRINT THEM!

With that said, digital is the way to go if the original is misplaced, damaged, or lost. With digital photos, you can easily copy and share at no cost. I keep 10 years worth of digital photos on my computer hard drive. I keep 2 backup copies of them all, one copy each, on two separate external USB drives. Many people now pay a monthly or annual fee to save their digital photos in the cloud (a pay-as-you-go web site).

I've found one of the most inexpensive, reliable, and convenient portable hard drives is the Western Digital Passport drive. It will fit in your shirt pocket and hold up to a terabyte (that's more photos than you can take in a lifetime). Mine are only 320 GB (gigabytes) but they should last for years. I bought my first one about 6 or 7 years ago. It's still good. I save photos in the camera's JPEG format. It seems to be universal and willl probably be around for years. Here's a photo of two of my WD Passport drives:

Get an external hard drive. Make copies of your digital photos often. Keep at least two copies of every photo, one each on separate devices (I keep 3 copies). Many even keep a spare drive or other media off site. That is, they make a copy and keep it in a safe deposit box or leave it at a relative's home. What a wonderful way to preserve your precious memories in case of disaster.

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