Question about image size

[jpdenk]

I just posted some entries in the photo of the month thread, all my images were 1,024 pixels in the long dimension, yet they showed up much smaller in my posting.

What am I doing wrong?

John

[Staff]

You aren't doing anything wrong.

The issues are on our end. We have been trialing image management software for the past four days. We have eliminated two from our selection process. We are attempting to work with the application currently in place to increase the KB's.

Images uploaded that exceeded 500 KB were prohibiting WG's dial up users from viewing more than the thumbnails. One third of all WG members are dial up users. Many of the images uploaded were in the 900 KB plus range. As new digital cameras with higher mega pixels become increasingly more available, we knew we would be seeing images with even higher KB's being uploaded.

We apologize for any inconvenience. Our goal is to find an application that will automatically reduce uploaded images to a size that fills the screen which would be somewhere around 450 KB.

We ask for your patience and understanding while we attempt to find an application capable of being configured to allow for better viewing of detail in images while not "going off the screen" when enlarged. The end result of our trials may be reverting to our original image management application.

[jpdenk]

Thanks for that info. One of my files was slightly over 500 KB, didn't realize it was that big. I try to keep file sizes down. The others were significantly smaller.

John

[Staff]

We're tweaking. We hope to resolve the issues this week.

[Cirsium]

Just for reference purposes, it takes 3 minutes per MB (1000KB) to open a photo on a good dial up connection. A lot of the photos that have been posted are in the 1.6 MB size category. That takes about 5 minutes to look at a full size photo.

Photos in the 1000 pixel size range fill most monitor screens, so it's a nice target size to shoot for. Many digital cameras today have a standard size of 2500 - 3000 pixel size range.

The other factor that affects photo file size is the pixels per inch specification. 70 to a 100 pixels per inch is all that is needed to give a high quality image on a computer monitor. 70 - 100 pixels per inch would not be adequate for a high quality print image, and this may be where some of the confusion comes from.

[jpdenk]

Originally Posted by Cirsium

Just for reference purposes, it takes 3 minutes per MB (1000KB) to open a photo on a good dial up connection. A lot of the photos that have been posted are in the 1.6 MB size category. That takes about 5 minutes to look at a full size photo.

Photos in the 1000 pixel size range fill most monitor screens, so it's a nice target size to shoot for. Many digital cameras today have a standard size of 2500 - 3000 pixel size range.

The other factor that affects photo file size is the pixels per inch specification. 70 to a 100 pixels per inch is all that is needed to give a high quality image on a computer monitor. 70 - 100 pixels per inch would not be adequate for a high quality print image, and this may be where some of the confusion comes from.

Actually, the pixels per inch figure has nothing to do with viewing, it only affects size when you make a print, and does nothing to change file size, so no matter if a photo is 300 ppi or 72 ppi, it will still be the same file size and will be the same size when viewed on a monitor.

John

[Fearless Weeder]

We are attempting to address the file size issues.

We thank you for your patience and understanding.

[jpdenk]

Originally Posted by Fearless Weeder

We are attempting to address the file size issues.

We thank you for your patience and understanding.

As an example, here on my Flickr page are 2 versions of the same photo, one is 300 ppi and the other is 72 ppi, essentially the same file size and look exactly the same on-screen. The 300 PPI image is actually a slightly smaller file size than the 72 PPI version. Same resolution, same amount of image compression.

John

[Cirsium]

Actually, the pixels per inch figure has nothing to do with viewing, it only affects size when you make a print, and does nothing to change file size, so no matter if a photo is 300 ppi or 72 ppi, it will still be the same file size and will be the same size when viewed on a monitor.

Thanks for correcting that. I have been known to get my ppi and dpi confused on more than one occasion.

[jpdenk]

Originally Posted by Cirsium

Thanks for correcting that. I have been known to get my ppi and dpi confused on more than one occasion.

You aren't the only one. PPI and DPI seem to confuse a lot of people. I had to read a book or two on imaging to get it straight.

John