coin photography:why do some pics compress down to 10kb(icon size) while others do not?

1907Quarter

using irfanview and I don't know when which pic will allow me to make it into an icon-can anyone inform?

ziggy29

If you're using software to edit and manipulate images, you should be able to control both the size of the picture and the quality of the picture (i.e. more compression = lower picture quality). With those two factors it's generally pretty easy to get most 100x100 pictures to a fairly small size.

1907Quarter

but for whatever reason, when using irfanview last night SOME, not ALL pics had a minimum limit of abot 36kb at the 99x99 level no matter how much I compressed. any idea why?

1907Quarter

ttt, the pic of th ME st. qtr I can get as small as I want (file size) but not others....very perplexed...might it have anything to do with how big the file size/memory size on the initial shot when it went into storage?

1907Quarter

or does it even matter if I crop first, resize second, or vice versa?

nwcs

One thing to keep in mind is the complexity of the image. With jpeg compression (and with most image compression techniques) the simpler the image (less going on) the more that can be compressed. Size also makes a difference as well. The less there is to begin with, the better. Also, with lossy compression like jpeg you can specify how much you are willing to sacrifice clarity for size.

Also, always crop to the image. Then size the result to where you want, then save.

1907Quarter

so i may not be able to crop an initially shot 2048x1536 down to 100x100 and 10kb but a 640x480 initial shot IS?
Also, I guess I would need to fill the field as best as possible with coin to create a smaller initial file size?

LanLord

What color are you using as a background for your coins? If you have a colored background it will add a lot to the image size and therefore work against you trying to get down to a 10Kb file size

ziggy29

<< <i>so i may not be able to crop an initially shot 2048x1536 down to 100x100 and 10kb but a 640x480 initial shot IS?
Also, I guess I would need to fill the field as best as possible with coin to create a smaller initial file size? >>

Use a plain background and crop out as much of it as possible.

Usually, what I do is this: I take a picture using high-res mode (3.1 megapixel) with my digital camera. The resulting picture is 2048 pixels by 1536.

Then, before I scale the size down, I crop out the extraneous background stuff so I only see the specific item I'm interested in. Then, I scale the picture down to the size I need to get down to, and then save it as a JPEG file, sliding the compression/picture quality value to the appropriate tradeoff between file size and quality. I've never had trouble getting a coin picture down to 10K or less if I make it icon sized or less.

nwcs

Yes, that is correct. When you resize from a super sized image, the resulting image is ALWAYS bad when made into a 100x100 space. If you start at around 300 to 400 pixels and then resample down, your results will be much better.

1907Quarter

I tried everything that everyone mentioned-no go. And then I remembered. Those coins I successfully got into icon size(<10kb) I had ROTATED before the final step of getting them from the camera to the first computer save!! This brought the pic past the threshhold. I went from 82kb to 55kb (on a 640x480 pic) with a simple rotation. Evidentally, according to airplanenut, it's how the computer photo software reads the color differences.
Has anyone ever encountered this before? I now know that if I want to make an icon shot, to shoot it upside down! As Brian Fellow would say-"that's crazy!"