Images compressed

[Carson]

This is probably very basic (which suits my user level) but why do JPEG files downloaded with Irfanview end up a tenth of the original size? How can I achieve lossless downloads?

[JendaLinda]

You are really not downloading images using IrfanView. It can't do that. You are probably opening images from your web browser in IrfanView and then saving them.

[Bhikkhu Pesala]

JPEG files from a digital camera are usually very high quality (98-100), and low compression.
The file size can be reduced significantly by using high compression, and low quality.

JPG (or JPEG) images of landscapes or seascapes can be compressed heavily without too much loss of quality. Images of buildings, machinery, or text display artefacts even at medium high quality settings (75 to 90).

Images of text are best saved as lossless PNG images, providing the highest quality with good compression.

See my help page on Image Formats.

[Carson]

Thanks very much to both. Perhaps I should be more specific. Since installing Irfanview I find it 'grabs' every image I download, from whatever source; that's what I intended to describe. I can't see any way of changing that. So ... I have been sent links to access/download hi-res images from a picture library to use for printed illustrations. The data from the library indicates their images consist of megabytes in the 20s and 30s. But when I clicked and downloaded I found I had images around 3 MB. Consequently I asked my printers to download them, and they got them full size. I don't see that anything could have interfered with the compression in this way other than Irfanview. I'd like to know if there's an instruction in the Irfanview program to ensure I always get lossless downloads. Thanks!

[Bhikkhu Pesala]

Use Windows File Explorer to see what the file size is after you have downloaded them. IrfanView won't compress them unless saving them.

[JendaLinda]

Check your Downloads folder, your original files should be there.

[Carson]

Thanks - I figured it out for myself. I was, of course, saving images (to publish them). I found a dialogue box that shows up when saving JPGs and GIFs where you can enable saving 'with original JPG quality' which seems to let them through without compression. Never had this problem with TIFs or other formats!

[JendaLinda]

You are still doing something wrong, because downloaded images normally don't go through Irfanview. You are not supposed to save downloaded files in IrfanView.

[IrfanUserGuyxyx]

Sounds like IrfanView, your default image viewer, is called by the browser or whatever you are downloading with to see the downloaded file. It has already been saved, as JendaLinda indicated, probably in your Downloads folder. You should be able to make the browser stop viewing the images as you download them. Usually there is a dialog that lets you choose to save or view the file. Try just closing IV instead of saving. Then look for the file in Explorer.