Holdrens Loc: originally Wellsboro, Pa

I have a Canon Rebel T3. When I download the pictures to my computer they are varied sizes (7.19MB, 8.11MB, 6.34MB, etc). Why do they download to such a large size if most sites/e-mails prefer them to be less than 750MB? (I have Windows 7 if that makes a difference.)

BrandyVSOP Loc: Oregon USA

Downloading them only transfers them from your camera to your computer. It has nothing to do with how big they are or are not.
Your camera shoots images at a given "Mega Pixal". Say 8MP 10MP 12MP or ??? Once they are in your computer, you can re-size them to a smaller size for emailing or whatever... But save it as a new file or you loose your original. Say if your original file name is "image.0177.jpg" you might save the re-sized photo as "image.0177-RS.jpg" . I use RS for "Re-Size".

But the Larger the size of the "Mega Pixal", the larger size print your can make from your image original picture.This is kind of a simple answer but I hope it helps.

robertperry Loc: Sacramento, Ca.

I shoot everything at high resolution. Not only for large prints but also because it records the most information. If you know you only want small prints or to send them email, you can go into your camera's settings menu and change resolution to small. You will be able to shoot more pictures on one card. Be aware of the down side of shooting small res. images, if it's that once in a lifetime shot, you can't make a large print.

SQUIRL033 Loc: Chehalis, WA

the reason images vary so much in file size (MB) is because of the varying levels of data in each image. a photo with lots of detail - leaves, branches, etc. - will take up more space than a photo of blue sky and a couple of clouds. this has nothing to do with image size in Mp... that's determined by your camera's sensor. your T3 is a 12.2Mp camera, and your files will all be 12.2 Mp, regardless of how much space they take on the hard drive.

bobmielke Loc: Portland, OR

Actually this is the first forum I've joined that has such a small limit on size. There are photographic forums that automatically resize your posted photo but allow the view to click on it to get a bigger size. Other forums only allow one thread a day to be posted of any size.

arphot Loc: Massachusetts

Same here. I've never had an issue with other forums. You can link from Flickr to here and post a larger size image but the rules say keep the width to 600 pixels, which (IMO) isn't really big enough. So, I try add a link to the original (when I remember) so anyone can see a larger size should they want to .

BOB Loc: Texas

About the down loaded pic on computer. why do they all have different sized mpix like on a photo shoot you take a dozen picture with a 10MP camer and some of the pic are 6.2 mp , 8.1 some 7 mp ??? what determines the final mp of the photo?? It doesn't match the camera mp?

bobmielke Loc: Portland, OR

The amount of detail in photos determines their final size. Such things as grass or leaves make for large complex images that wind up being bigger. Squirl033 pointed this out earlier in this post.

Holdrens Loc: originally Wellsboro, Pa

Thank you everyone, I do appreciate it. It all makes sense now. (at least on this subject)

BBNC

High resolution in the camera is the way to go. You can always resize and/or print at smaller sizes for snapshot and other use. I have an SX30IS set on its highest resolution (14Mp). Today's memory cards give a lot of picture taking for the buck. An 8Gb card holds more than 2000 14Mp images, far more than I can shoot with two batteries. Each battery is only good for 300 to 400 shots. When I'm working at it, I can get some 400 shots in 2 days, but that becomes a bit like work. 16Gb and above are primarily for video.

marcomarks Loc: Ft. Myers, FL

By the way, that's 750KB (kilobytes or thousands), not MB (megabytes which is millions). So...

Your camera creates large file sizes to contain 12 million pixels. That many pixels are not needed to look at a photo on a computer screen which can only show you a maximum of 72 dpi. Anything you look at on your computer screen is seen at 72dpi even if it's a 300dpi file in the first place.

Large MP files are needed for purposes of printing at 300 dpi. So when you put the files on your computer hard drive, they are the big MB files jammed full of many megapixels so you can print from them later.

A website or e-mail recipient doesn't usually need you to send them 12 million pixels because it takes a very long time to receive and download the picture file. For example, on a website that has 10 photos on it, if they were huge MP printable files, the website page would take forever to load onto the viewer's screen. If they're small MP viewable-only 72dpi files they download very quickly so the screen pops right up. If the photo creator (you) did a good job of re-sampling a copy of the original huge file down to 72dpi for web transmitting purposes it should look very much like the huge printable file but is small MP and the file is small MB. Re-sampling causes a little bit of blur so most times the file isn't quite as good as the original. Sharpening during the re-sampling helps but it's still not perfect.

E-mail recipients many times only have a 5MB or 10MB mail box to work with, so if you sent them one 8MB 12MP photo file, it would fill 80% of their mail box so very little other mail could get in before it was full - or one of your pictures would try to overfill it and be rejected. So you create considerably smaller files through re-sampling that are 72dpi and you can send many of them attached to an email.

Most times, my 72dpi e-mailable files are 490KB or 500KB, which is less than half of one MB in size. 512KB = 1/2 of a MB which is a long ways from the original 6, 7, or 8 MB file you started with. 1/16th the size, in fact.

This is why when people download a friend's Facebook photo and try to print it that it looks terrible. The 72dpi Facebook photo only has about 1/16th enough resolution to print (if that much) and the result sucks big time.