Size of a digital image is how many pixels (picture elements) it contains. This is usually seen as so many pixels high by so many pixels wide, such as 350 x 279. This would appear as a relatively small photo, while a larger image may be 1600 x 1200.
As we begin to 'use' our images by sending them by email, or uploading to an on-line photo album to share with friends, a different unit is used to measure size: kilobytes, or KB, as it is most often seen. This unit is also used to measure document and other files processed by our computers.
Where size has proven to be important is when our photos are viewed by others. What is actually done is that each viewer's computer must download a copy of the photo in order to display it on our monitor screen. The larger the photo and the more KBs that it must process, the longer this will take. We often wait several minutes for a medium sized photo to 'load' so that we can see it.... many times four or five minutes per photo.
I am not going to deal with size here, other than to point out that as we are working with our photos with either our camera or within software programs, we will see the photo sized as pixels. So how do we know just how many KBs our images are? Open your 'My Pictures' folder, or wherever you have your photo stored on your computer, and right click on an image. Click on 'properties', and it will give you the size in KBs... often pausing your cursor on the image will popup a little box with the properties.
(I will venture one personal opinion here. The only 'waste' of time I have little patience with is a photo in which the African violet plant is a small object in the center, and the majority of the photo is of the surroundings. Artistic sensibilites require a bit of free space around the object, but I feel the African violet should make up over half of the area in a photo. Personal opinon....)
Quality, as applied in this lesson, is the level of compression that the camera will use when saving your image to the camera's media card. They may be divided into sections such as 'Good' or 'Standard', 'Better' or "HQ-high quallity', or "Best' or 'SHQ-super-high quality'. This goes back to the number of photocells recording data and the number of pixels that make up the image file.
I personally noticed a great deal of difference between the Standard, lowest, quality and the High Quality, middle, setting on my camera. There was also a step up in detail and color accuracy when I went to the Super High Quality setting.
Going back to the notion that the image captured is our digital 'negative', then my advice is to begin as large as you can and then make a smaller copy to use for emails, and maybe a medium sized copy to store in a photo album. In effect, you are using a great negative to 'make' smaller 'prints'.
If you don't think there will be much difference, try this: make a small photo your desktop background. Then use a larger photo! Or simpler still: print out a 4 x 6 print. That's not large, but even at that size, the original quality of the image will be evident.
One note of interest, which I just discovered while taking photos for this lesson: the higher qulilty setting seemed to require a bit less light. In other words, the exposure and color balance was better the higher the quality. To put this into use: if you are having trouble with camera shake or blurry photos in low light situations, try a higher quality setting. (The following photos were taken with Automatic exposure settings...if you were using manual settings you would be compensation for any differences, and would not notice this effect.)
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