"HOW TO" Guide to resize and compress photos (slightly more advanced)

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adampembs
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"HOW TO" Guide to resize and compress photos (slightly more advanced)

Post by adampembs » Sat Sep 26, 2015 7:47 pm

There is a major limitation with Microsoft Paint, as used in the "easy resizing tutorial" - there is no way to change the compression of files you take with your camera. This means that even when you resize to say 1200 x 800 pixels the file is not compressed much and can be way over the 400k file size limit. This is why some people are reducing their photos to very small sizes (like 640 x 480px, which appears very small on screen)

Jpg files were designed to be compressed. They are very efficient at this, so they can be compressed by 90% or more, without any noticeable difference in quality.

I use two tools for doing this. One is Google Picasa, which is the one I use for organising my albums. This is available from http://picasa.google.co.uk/

Another tool is "paint.net" which can be downloaded by logged in members from
http://fungi.org.uk/uploads/pdn.zip - I have scanned it for viruses

Download this ZIP file and extract it. Then run it to install. You may get a warning about it , ignore this and accept any agreements.
The resizing is as follows.

Open Paint.net and click on file, open. Browse to where your file is and open it.

Click on "image, and resize" as below
resize.jpg
Then you should see something like this (from your camera the width and height might be 3000 or 4000)
1280.jpg
For this example, I have resized from 1280 to 1024 but for fungi.org.uk, I would recommend changing the number in the box to something in the range 1024 to 1600 (try a few out.) You only need to change one number, the other will scale automatically.
1024.jpg
Then click, file, save as, and choose where you want to save it. You should either give it a new name or save it somewhere else, so you don't over-write your originals.

This is where the compression comes in. Notice that at a compression of 95, the predicted file size is 442k and too big to upload to the forum.
184.jpg
If you lower the quality to 70, the predicted file size drops to 184k and is plenty small enough for the forum. You can vary the compression and see the result, but 70-80 is what I would recommend.
442.jpg
If you have any questions or anything is unclear, please let me know.
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MykoGolfer
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Re: "HOW TO" Guide to resize and compress photos (slightly more advanced)

Post by MykoGolfer » Sat Jan 09, 2016 5:06 pm

I also have Microsoft Office Picture Manager that compresses and resizes pictures.

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