How to properly reduce digital photos in size?

How to reduce digital photos in size?

When you insert digital photos from your camera into any application like PowerPoint or Word without preparing them first you will run into problems. What happens is, even after just inserting a few pictures the filesize of the document will be enourmous, clogging up your email account and/or your hard disk pretty quickly.

Resizing pictures inside e.g. Powerpoint or Word does not reduce the physical size of the picture, just the visible representation in that particular document. The data file in the background is still the same size.

Example: You took a digital photo. At 10 megapixel the photo has a resolution of 3648 x 2736 pixels and is about 4 MB (= approx. 4000 KB) in size.

If this picture is inserted into Powerpoint for a homework assignment, and even if the visible size is reduced with the little black handlebars, the picture will still be a whopping 4MB.

Now add four more pictures from the same camara and you end up with a file of approx. 21 MB!

Most email providers will never allow this to be sent and/or received, not taking into account that it will take close to forever to send this email.


So, how can you avoid this?

Easy: Reduce the physical resolution of the picture without damaging the original. Always keep the original, in case you want to have them printed later or modify them again.

Rule of thumb: Never work on originals, always use copies!

Accepted resolutions for web use and/or use within documents (Powerpoint, Word, E-Mail, etc.) are:

160 x 120 - small - small enough to leave room for text
320 x 200 - bigger - already covers a quarter of the Powerpoint sheet
640 x 480 - medium - covers almost the entire Powerpoint sheet
800 x 600 - large - significantly bigger than the Powerpoint sheet

Note: Everything after 800 x 600 is too big for this specific purpose.

Have a look at the example screenshot taken from Powerpoint (see below). Notice how large even a 160 x 120 picture is in Powerpoint?
Tip: How can you check if your picture is scaled or full size? Right click in the picture and select "Format Picture", then select the "size" tab. "100%" percent means, the picture is not scaled, but shown at it's original size.

 

Note: We are going to use the free, open source AFELO picture compressor for this example, but feel free to use whichever software you prefer. If you want to download AFELO please click here. It is available for Windows, Mac and Linux and the only prerequisite is a fairly recent Java Runtime.

For this example, we want to insert 6 digital photos into a powerpoint presentation and write a short story about how, where, and why we took them.

As the filesize of the photos alone would exceed 21MB we are going to reduce the physical size of those 10 megapixel pictures before we add them to the document.

Step 1:

 

  • Remember the rule of thumb? Never work with the originals! Create a folder on your desktop, name it appropriately. In this case we named our folder "My Homework"

  • Copy (not move!) the pictures you want to use into this folder.

  • Start AFELO, then click on Compress & Upload Images

 Step 1

 

  • Next select if you want to convert one or a folder full of photos.
    For this example select All images of one directory

Step 2 

Select the photo(s) or the folder with the photos you want to reduce in size. This is basically a file menu you know from PC and MAC applications like Word or Powerpoint.

Step 3

A: You can jump to the  M y Pictures, to the Desktop if you placed your pictures on the Windows/Mac Desktop, My Documents quickjumps to the My Documents folder. Another Directory will bring up the usual Windows/Mac file selection dialog box.

 

B: If you selected any folder containing pictures they will show up here. Select one or more and click on Forward.

C: The icon with the orange arrow allows you to move UP in the directory structure. The other icons that might show up to it's right are the folders/directories contained in the folder you selected under point A.

 

 

Double clicking on Desktop, then on My Homework gets us to the folder we want to convert.

Step 3

Step 2:

After clicking on "Forward", leave the setting drop down box on "optimize for the web" and select one of the offered resolutions. You might have to experiment a bit until you find the one right for the job.

As a guideline: 800 x 600 is very big, but still significantly smaller filesize wise than the original. If you need lots of details and are unsure, go for this resolution. Check with the example at the beginning of this guide.

Step 4

Step 3:

Next step. AFLEO lets you modify the selected picture(s) in this step. Double click on any of the thumbnails on the left. The picture will then be shown in the main viewarea.
Now, you have the option to: Crop the picture, turn the picture clockwise or anti-clockwise, make the image brighter, convert it to black & white, adjust the brightness, contrast hue and saturation manually or reset whatever you changed. When you are satisfied, click on "Forward".

Step 5

Step 3

Step 4:

Now for the most important part. Where do you want to put the resized pictures? AFELO can put them on your Desktop in a new folder it will create, labeled with "AFELO_IMG_YEARMMDD_TIME". Example: "AFELO_IMG_20090407_1515" This was saved on 7th April 2009, at 3:15pm. Or you can save it to a folder you specify.

Step 4

After Afelo is done it will show the new loction of the converted images:

Now let's compare filesizes before and after the operation. The original 10 megapixel pictures combined filesize was close to 22 megabytes, that is approx. 22.000.000 bytes. After the resize operation this has been reduced to just over 386 KB, which is approx. 386.000 bytes, from 22 megabytes to less than half a megabyte!

Immediate benefits: The document will look the same, but it will a) load significantly faster, you will not have PowerPoint crashing on you react in super slow motion, sending this document via email will only take seconds and -not unimportant- the teacher's computer will have no problem opening this document.

Result

 

As you can see, choosing the right resolution saves a lot of memory.

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