Image file compression with OpenOffice 4.1.0

[SweetPea_SuperMoon]

Hi everybody!!!

Does anybody know how to compress image files using the new Open Office 4.1.0? I see there are tools out there for the older versions of Open Office but none of my searches have turned up anything for 4.1.0.

I'm using O.O.4.1.0 to send scanned, written assignments to my distance learning teacher, and if I can't figure it out, well I'll be darned. I don't know what I'll do!

Any help would be magorly appreciated.

Thanks!!!

[John_Ha]

Welcome to the forum.

AOO Writer does not compress images when producing an ODT file. So, if you want to minimise the file size, you need to try the following.

1 Send a PDF. You can use the File > Export as PDF dialogue to compress the images to whatever dpi you choose. Be aware that the AAO compression routine is not as good as, for example, the best compression routine in IrfanView, and leaves artefacts even in lossless compression. In this case, it does not matter how big the images are in Writer as they will be smaller in the created PDF.

If you want to send an ODT or a DOC file etc, then you need to minimise the image size before putting it into AOO. It is a good principle to do all image processing in an image editor, and not in Writer. IrfanView is an excellent, easy to use, free image editor (I think it is among the 10 most downloaded programs of all time - it has taught me everything I know about image processing) - so too are things like Photoshop, Gimp, Picassa etc.

First, you need to treat photos differently from graphics (graphs, clip art, cartoons, pie-charts, anything with text)

1 Decide how big the image will appear when printed - say it will be 3". 150 dpi (dots per inch) gives good printing quality, so the image needs to be about 450 pixels wide. Re-sample the image in an image editor to be 450 pixels wide and save the file as a JPG if it is a photo, or as a PNG (excellent), GIF or TIF if it is a graphic, before inserting it. My camera produces 14 megapixel pictures which are 4,500 pixels wide. Reducing them to 450 pixels wide makes the file 100x smaller.

2 If you have a photo, be sure to use JPG to store the original image file. If you have a graphic or clip art or anything with text be sure to use a lossless compression format like PNG (excellent) or GIF or TIF. Lossy compression like JPG is fine for photos, but it ruins the quality of graphics. You must use lossless compression (like PNG, GIF or TIF) for graphics.

3 If you insert an image by Insert > Picture > From file ..., or by dragging it into Writer, then Writer stores the image in the file format of the selected file. JPG is stored as JPG, and PNG is stored as PNG. This is good.

4 If you paste an image in from a file, Writer stores it as a PNG even if it is a photo. A PNG will not be affected, but a JPG photo will be about 3x as big when stored as a PNG file, compared to when it was stored as a JPG file. This may be bad news - a 14 megapixel photo from my camera is typically 5MB - if I paste it into AOO it is typically 15MB. So it's fine to paste in graphics, but it's bad news to paste in photos.

5 If you really want to make the images smaller in size, then reduce the number of colours in the images - this reduces the file size by 3x compared with 24 bit files. Try using 256 colours for graphics and clip art - but never for photos.

IrfanView - Decrease colour range dialogue

IV decrease colour range.png (9.76 KiB) Viewed 2991 times

6 If you are desperate, reduce the Quality Factor of any JPG files when you store them. The lower the QF, the smaller the JPG file - but the worse the quality. 85 is usually a good compromise.

IrfanView - Quality Factor dialogue on saving as a JPG

If this solves the problem, please edit your original post title to [Solved].

[nehavilash]

For knowing detail information about the image compression, you can go through the official documentation of OpenOffice and export your document as a PDF with file export. Adjust the dpi for smaller size. For best result preprocess images in IrfanView to resize photos on the other hand you can compress your images with online application such as https://jpegcompressor.com/ it compresses the images without losing their quality.

Thank you.