Need help converting Jpeg images to less than 500kb

[jayadams22]

Could someone please give me a step by step guide on how to change the file size of my pics. I tried downloading the riot plug in but it didn't work.

[Bhikkhu Pesala]

The RIOT plugin (save for web) is the best route. It should work if you installed riot.dll in the right place.

C:\Program Files\IrfanView\Plugins

Check in Help, Installed Plugins…

Otherwise, you can do it by saving as JPG directly from IrfanView. Adjust the quality slider to about 75 or 50 at the lowest and if the image is still too big or the quality is unacceptable, you will have to resample it first (Ctrl R) to reduce the number of pixels.

[Thoskk]

Two simple ways to change the file size of an image

If you want to change the file size of your images and are not using the riot plugin, there are 2 ways in general. At first, it's changing the format to a format with a (higher) compression. A second way is changing the picture size.
Since you wrote that you are using jpeg, I will first explain how to use this format, since it offers compression:

1. Open the image
2. choose "save as" from the File menu
3. from the available format menu (the "Save as type" menu, below the "File name" input line) choose JPG - JPG/JPEG Format
4. activate the "Show options dialog" box
5. in the "JPEG/GIF save options window (mostly opens to the right), choose a compression (and leave the first three boxes unchecked)
6. save your image under a new name (so you don't overwrite the old image)

If the file size is still larger than expected, either choose a higher compression or change the image size. Note that a higher compression in JPEG reduces the quality of the image. However, a reduction in picture size has a similar effect, dependent on the resizing filter.
To resize the image, do the following:

1. Open the image
2. choose "Resize/Resample" from the image menu
3. check the "Preserve aspect ratio" box, if you want to keep the original aspect ratio of the image
4. decrease the size of the image, e.g. by choosing a standard dimension from the dropdown list
5. activate and choose a resampling filter (usually the quality increases from fast filters to slow filters)
6. if you want, check the "Apply sharpen after Resample" (but this usually is only necessary when you increase the image size)
7. click "ok"
8. save the image under a different name

If the image still is too large, shrink it again, or choose a higher compression, or a combination of both.
In addition to the jpeg format, there also are formats that use a lossless compression. For more information, you can have a look at this Wikipedia article about image formats.

[Thoskk]

As Bhikkhu Pesala already mentioned, the RIOT plugin is way easier to use. Check if you have it installed in the plugins folder (within the irfan view folder). If not, install the plugin version that suits your irfan view version, and you will see how easy this can be.

[Skippybox]

RIOT is very good because it has the Compress to Size function. In other words, typing 500KB in, will do most of the work for you, to get a file size just below it.

You can either use File>Save for Web which will let you do one image at a time with a preview, the Save As dialog for single images as well, or use Batch Conversion which will do many.

In the batch dialog, if you choose Options next to Output format:JPG, you will get the same little dialog as options in Save As. You will notice the last item for JPG is Set file size.

You can also skip compress to size, and just use RIOT's other options, or use them together. RIOT can resize images if you need.

You may find sometimes that it will be useful to not preserve EXIF or other information in the file, since it can take up considerable space. Sometimes JPG is not the best format, and PNG may actually deliver smaller file sizes, along with delivering better quality!

Remember, don't overwrite your originals! Always back up these high quality images.

[Art B]

Cropping and KB's

To resize the image, do the following:

1. Open the image
2. choose "Resize/Resample" from the image menu
3. check the "Preserve aspect ratio" box, if you want to keep the original aspect ratio of the image
4. decrease the size of the image, e.g. by choosing a standard dimension from the dropdown list
5. activate and choose a resampling filter (usually the quality increases from fast filters to slow filters)
6. if you want, check the "Apply sharpen after Resample" (but this usually is only necessary when you increase the image size)
7. click "ok"
8. save the image under a different name

When cropping an image why does the weight not decrease? If I crop 50% of an image the number of KB's reamins the same as it was prior to cropping?

Art

[Sam_Zen]

I'll exclude the option to resize the bitmap, because I don't think it is part of the question. It's about filesize of an original.
In this case, apart from which method (RIOT is the best of course), it's first the case, as pre-stage, to look at the number of colors used.

It depends on the character of the picture of course, but sometimes it can be decreased to 256 or even less, before any further action.

In this perspective, as Skippybox mentioned, PNG does a much better job than JPG. The latter just keeps it full-color, while PNG checks the number of unique colors used and saves it that way. With surprisingly small result sometimes. One can check this with the 'I' key.