![]() The original / jpgmini / irfanview jpg85 produced an exceedingly minor variation in visible quality in a few places using 3 image flicker comparison. Jpgmini and irfanview jpg85 were indistinguishable in result using a flicker comparison test and very close scrutiny at 100% crop (ie monitor pixel per image pixel). At jpg90 the files size is modestly greater than jpgmini achieves and at jpg80 it is essentially idential (!1.9 MB down from 9.97 MB for the original.) I save dthe original using Irfanviews at jpg90 and jpg85 settings. I downloaded a jpegmini trial image from their site (creative commons licence) and their compressed version. JPEGMINI is not an obviously useful improvement on eg Irfanview at JPG90 setting. As long as you keep the master file JPG90 is usually good for most other purposes. If you really really care then maybe JPG90 will destroy data you'd like to keep.So eg 2 GB of travel photos would typically reduce to 256 MB with an image size filling more than 4 x 1080p monitor screens. This will print in A4 at over 300 dpi which is more than can genuinely be used by most colour printers = a long and loud discussion for another forum :-). If you can tolerate a 1/2 res = 4240 x 2830 = 12mp image then you get typically 8:1 compression for sending to people. On 6000 x 4000 = 24 mp Sony A77 images JPG90 compression gives typically 4:1. eg Garden of small many coloured flowers may compress almost not at all and helicopter far off in blue sky may be massively compressed. Minimum compression I get except in special cases is about 2:1 and 10:1 can happen (rarely) with some images. For all except the very most discerning of applications * jpg90 works very well.įor explanation of the basis for this obviously subjective and probably somewhat contentious claim, and a description of how supporting measurement was made please see " Achievable compression quality at JPG90" & " Flicker Comparator" below, Irfanview jpg90 setting produces compression ratios that vary with image content and camera setting but which produce an image quality that takes intensive "pixel peeping" to tell apart from the original. The only way to compress files while retain the identical quality is to use a " lossless compression" system which does not destroy image information content but which uses some means of coding the available information into a smaller format.įree and fabulous and well established Irfanview probably will too.Īnd so will many other free programs, using appropriately applied compression systems. "High image quality" is of course subjective. Please see the " Compression & Quality" mini-tutorial at the end of this post. ![]() How can I resize all images while retaining high image quality?Įxtra comment: Image compression and quality:įor comment on matters related to image compression "quality", and terms such as "lossy compression", "lossy compression", "high quality" "flicker comparator" and similar, I have more then two gigabytes of travel photography.Įach image takes up than 4 to 5 megabytes. Upload once and all your friends can look.īest of all, by choosing the best images and not bothering with the others, you are literally increasing the average image quality and saving bandwidth and storage. ![]() I'd suggest an online web gallery service for sharing, rather than e-mail. Or, if you do, since you have fewer photos to work with, you can be more careful about selecting the best parameters for each one individually rather than mashing them all down in bulk. You may find that with this reduced data load, you don't need to resize at all. An album of 40-50 good, interesting photos is better than a big dump of half a thousand unsorted ones.Ĭhoose images which show the story of your trip, and which present a unique point of view not available in postcards. Take some care and write a meaningful caption for each one. Instead, go through and pick out the very best 10%. Even your close friends probably don't want to wade through all of that. If you have 2GB of images at 4-5MB each, that's somewhere between 400 and 500 images. I think you're going about this the wrong way. ![]()
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