OK, here is the topic recently spawned elsewhere. I guess I'll let the various experts chime in and explain all. Click here for the 10MB download version of this topic.

_________________
--Mike

You fooled me with the "Click Here".

My basic premise is that your monitor will display only about 72 dpi and one will not be able to tell the difference in a 1MB image and one that is 200K, with the size of the image being the same. Printing the image is a totally different matter.

_________________
--------------------------
Roy Rogers
Southern Tampania de la Floridana Universidad (STFU)
STFU Motto: All Bamboos are not Created Equal; @ STFU, the Search Continues
**********
ROY'S BAMBOO LIST

I think most windows based systems display at 96 dpi as opposed to apples at 72 dpi. Or at least that's what it was quite a few years ago. The difference between say a 200k image vs a 2MB image (ceterus paribus) is what you see when you zoom in on the image. At 200k, if you'd zoom in beyond a 100%, you'd probably get jaggelies. At 2MB, you'd get more detail if more detail were to be had.

Here's 2 links to 1.6MB. 1.9 MB and 1.7MB images. You may see more because the images are larger, but there is no visual detail dilfferences because you can see clearer detail, which I don't see. And I am on a Windoz machine.

Now if I have an expensive high resolution monitor or I print the images, then I believe I will see a difference.

http://tinyurl.com/kjjro

http://tinyurl.com/h5hmg

http://tinyurl.com/hh92w

_________________
--------------------------
Roy Rogers
Southern Tampania de la Floridana Universidad (STFU)
STFU Motto: All Bamboos are not Created Equal; @ STFU, the Search Continues
**********
ROY'S BAMBOO LIST

Roy
If you click on the images the full size photos will come up.

I need to edit those to make them smaller. What I have been doing is cropping the photos so that the relevant part of the plant is displayed then adjusting the resolution.

In the 'Bory' shoots photo I would remove most of the dirt then see if reducing the dimensions by half would still show the detail. Currently the photo is 2560 x 1920 pixels so on my monitor you have to scroll over just to see a shoot.

Normally reducing an image by half does not distort the image and it reduces the file size to 1/4 of what it was.

There are some exceptions where high resolution helps such as showing the hair on a Ph. kwangsiensis culm. But then it can be a photo of just the culm so it does not need to show much area.

Bill

Hi Roy,

Below are two links to the same picture (Warning for dial-up users: flooded-original.jpg is 2MB!).
http://i101.photobucket.com/albums/m55/ ... lowres.jpg
http://i101.photobucket.com/albums/m55/ ... iginal.jpg

They both have equal screen resolution (2272x1704) and are both in jpeg format. Neither have been corrected in any way except for the low-res version where it was saved to create a file size at around 200K.

If you were to display both images at 100%, you should be able to see significantly more jaggalies in the low-res version. There is loss of detail in the shadows and in the highlights (e.g. where the snow meets the water, among the branches).

Granted, I'm probably splitting curlies (another phrase form my australian friend that I picked up), but I think that for images at least, size is a factor.

Bamboozal, I think Photobucket altered your images. Anything above 1MB is resized. Take a look:
<img src="http://img.photobucket.com/albums/v310/Thuja/properties_orig.png" border="0" alt="original"> <img src="http://img.photobucket.com/albums/v310/Thuja/properties_low.png" border="0" alt="low res">
Your original is lower resolution (less pixels) than the low one!

_________________
--Mike

You're right Thuja. Photobucket has indeed re-sized my pic! Is there any other way I can post the original 2MB pic? Or can I be taken on my word?

I saw that CJW posted some large photos on http://www.webshots.com.

_________________
--Mike

Just tried it but it doesn't seem to work either. It downsizes my original while upsizes my low-res.

I'm gonna try to find something else...

It might be easier if I offered to email both image files to whoever wants them.

Let me know.

I think I got it this time....

Original (2MB)
http://serv4.imagehigh.com/view.php?id= ... h=/imgs///


Low-res (180KB)
http://serv4.imagehigh.com/view.php?id= ... h=/imgs///

Yep, that worked and does show how the higher resolution photo contained more detail than the smaller one.

Ironically, I think you also produced an example that shows how more pixels in a photo doesn't always guarantee a more detailed picture. Both your photos are the same size (same number of pixels) yet the "watered down" (enlarged) photo shows less detail.

As I think more on this topic, I begin to realize that it is more complicated than what first meets the eye. In digital photography terminology, resolution simply means number of pixels. It doesn't tell you anything about the accuracy of those pixels. I think lots of confusion occurs because we intuitively think of resolution as meaning clarity, but it doesn't necessarily mean this at all. In any case more pixels (resolution) usually does show more detail, tho the degree of payoff is a function of many factors such as the camera, the photographer, the lighting, etc.

Here's a related topic that shows how the accuracy of the pixels makes a difference. Take color depth as an example. Each pixel can be assigned a finite number of colors. Here's what the same photo of the same resolution looks like with varying degrees of color choices:
<img src="http://img.photobucket.com/albums/v310/Thuja/photography/colorDepth.jpg" border="0" alt="color depths: 16, 8, 4, 3, 2, 1, 1-bit">
color depths: 16, 8, 4, 3, 2, 1, 1-bit
(65,000 colors, 256 colors, 16 colors, 8 colors, 4 colors, and 2 colors (last 2 photos))
And of course the photos with lower color depth will produce much smaller file sizes, uncompressed as well as compressed. Anyway, it's 7 photos of one of my daughters!

_________________
--Mike

More pixels is not always better, but for a given resolution, i.e. a fixed pixel count image, the image with a larger file size is always better. To address the topic title, when an image is compressed, pixels are not necessarily lost, but information (colour, light levels, etc) to varying degress gets tossed out of the window.

And your daughter looks adorable. Is she 3?
Looks just like my princess.

Also, Mike- Are you teaching hear the most important thing?- stay away from the Rubro