Sizing Pictures
First off, don't worry about me being here rather than horsing around on the Chainsaw Forum. I may be able to explain a few things about sizing digital pictures for display here on AS, so this is on the level.
When you get right down to basics, there are only two things that you want to do with your picture to post it on this site.
1. Physical Picture Size
When you take a picture with your digital camera, you're obviously not capturing the picture on film, but on a light sensitive integrated circuit. This circuit, often refered to as a CCD (Charge-Coupled Device) array, incorporates a grid of tiny sensors that each essentially respond to both light intensity and color and translate this information into electrical voltages or currents. The buzz word that everyone knows of course is Mega Pixels and this refers to how many of these little sensors are present on the CCD in the camera. All other things being equal (and there are many variables in cameras that are not), a larger amount of sensors, or pixels, results in a finer quality picture. If you multiply the number of vertical pixels by the number of horizontal ones in the rectangular matrix on the array, you will end up with this number. One of my cameras has an array that has 1312 vertical pixels by 2000 horizontal pixels. That works out to 2.6 MP, or Mega Pixels.
If I were able to post this picture on AS directly from my camera, those 1312 by 2000 pixels would translate directly to the pixels on your computer monitor screen. Typical resolutions on video cards for today's 17 inch monitors run in the 768 X 1024 pixel range. If you run much higher than that, the fonts just get too small to read. On a 21 inch monitor, you can get away with 1024 X 1280 pixels, but most people don't run 21's yet. At any rate, if one were to put a 1312 X 2000 pixel picture directly on AS, the picture would fill up more than the whole screen. You'd have to scroll around to see sections of the picture, but would never be able to see the whole thing at once.
Because almost all digital cameras nowadays have array sizes that exceed the resolution that most people have set on their monitors, it becomes necessary to reduce the amount of pixels, or resoulution, of the picture you've taken, so that people will be able to see the whole thing at once on their monitor. A good basic size to pick is probably in the range of 480 X 640 to maybe 600 X 800 pixels. You could set your camera to these resolutions before you take your picture, but if you later decide that you want to print the picture on paper, you might wish that you had taken the shot at a higher resolution. If you do have a picture that is too large, you will have to downsize (downsample) the image in a photo manipulation program. Any number of inexpensive programs are available to do this, so you don't have to go out and buy Adobe Photoshop for $600.
2. Picture File Size
We're lucky here on Arborist Site in that we can actually upload pictures from our computers onto the AS server for display. If this wasn't the case, you'd have to host them yourself on your own web site like Che does. Unfortunately, we don't all have that luxury, so it's great to have this feature for free (it's not that common). Pictures take up a lot of file space (much more than text). Che states that a picture's worth a thousand words, well that's probably even understating it in digital storage terms. Because of this, AS limits the maximum file size that your pictures can have to about 102 KB (kilobytes, don't ask, it really doesn't matter if you don't know what a kilobyte is).
So how big is the file of a typical JPEG (.jpg) picture? Well, if your camera is, say, a 2 Mega Pixel unit, then if you're set to the finest JPEG resolution (least file size compression, higher quality, therefore largest file), you'll end up with a file size of somewhere in the neighborhood of 500 to 800 KB; way too large for the AS maximum of 102 KB. Now, as with physical picture size above, you could set your camera to a lower quality mode (more file size compression, lower quality, therefore smaller file) before you take the picture, but again you might want to print the picture at a higher resolution and quality later. As before, in a resonable photo manipulation program, you should be able to specify the compression (hence quality and file size) of your file when you do a "save as". It should tell you what the final file size is before you click "OK", so you can play with it until it's under 102 KB.
One final note on printed picture resolution versus computer monitor resolution. You will find that printed pictures require much higher resolution than does your computer monitor. 72 pixels per inch for a computer monitor is just fine. When you do a high quality print, you'll want 300 dots (pixels) per inch. Note that this 300 dpi number is not directly related to printer resolutions like 1440 X 1440 and the like.
I've been too verbose as usual. Good luck.
, but it will show you the detail you can get on a quick shot with a fairly cheap camera (this fall there'll be farm/nature pictures)...
