Quote:
Originally Posted by Threadbanger
Hi - I scanned an old mag recently and then used Irfanview to rotate and crop the images. This is the first time that I have tried to do this and I was paying attention to the cropping and numbering of the finished images and didn't pay any attention to the file sizes until afterwards. The unadjusted images were generally around 2 MB in size, but after I had cropped them, they had like doubled in size. I don't know why that happened - I set the options to give me the best quality JPEG afterwards, but the file sizes are like 5 MB each now - which is a bit too big really ...
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Hi Threadbanger,
The "best quality JPEG" is probably the culprit at fault. Jpeg is a 'lossy' picture compression engine--this means that the higher the quality, the less information is removed from the picture, and therefore the larger the file is; also the lower the quality, the more information is removed from the picture, and therefore the smaller the file.
By altering your pictures (cropping, etc.) and recompressing the file, you have added more information to the file size.
Irfanview is attempting to retain as much of the original picture and rendering information as possible (i.e.: 'best quality'), therefore the file sizes of the new pictures are very large. To make smaller jpeg files, you will need to sacrifice the quality of the pics.
An alternate possibility is to try and use a 'lossless' compression engine, but many file host-sites do not allow these types of files.
I hope that explains things a bit. I am sorry that I couldn't help more.
e.d.
