Cropped images double in size - why?

[thorstenlemke]

Hi,please uncheck the add resource fork option.Thorsten I do not see why anywhere near 100% is needed if you check it out the file size increases exponentially right near there.GC [and Preview in a smaller way] start making massive files near over 98%Try the use of 95% or something like it?

[thorstenlemke]

Hello,JPEGs are often stored at 70-80%.Thorsten Were the originals saved at 100% quality? If you open an image that was saved at 90%. crop it. and then save it at 100%, there is a good chance the cropped version is going to end up with a bigger file size. Going from 90% to 100% can double or triple the size of the file.

[thorstenlemke]

Hi,can you maybe e-mail a source file for testing to lemke@lemkesoft.de ?Thorsten Hi, I am cropping a bunch of jpgs (simulation images) and saving the resulting files. Much to my surprise, the cropped images are nearly twice as big as the originals. One reason to crop is to reduce the size of the movie that will be made from the set of images, so this increase in image size is counterproductive. I tried both lossless and no compression, and the same thing happened. Suggestions? Explanations? Thanks!J. Karpen

[thorstenlemke]

Hello,I suggest to download the latest BETA:http://www.lemkesoft.org/beta.htmlIt will now display in the information window the source JPEG file quality (estimated).Thorsten Hi, I am cropping a bunch of jpgs (simulation images) and saving the resulting files. Much to my surprise, the cropped images are nearly twice as big as the originals. One reason to crop is to reduce the size of the movie that will be made from the set of images, so this increase in image size is counterproductive. I tried both lossless and no compression, and the same thing happened. Suggestions? Explanations? Thanks!J. Karpen

[David Morrison]

> > >I looked at the resolution and both the original and the cropped >image are 72 pixel/in. So I don't see how that could result in a >much larger file size. > >Out of curiosity, I then tried "Save As..." for one of the original >images without doing any cropping. The options were set to >JPEG/JFIF, 100% quality, and I clicked on each of the codec options >with "show file size" on. All 3 yield a larger file for the copy >than for the original, with the smallest difference being for >progressive codec. I also used the default subsampling -- is that >what is adding to the file size? The image size is 1419x1200 to >start with, if that matters. > >Finally, I tried the same test with a previously cropped and saved >image. This time the new (but supposedly unaltered) file is smaller >than the original. Go figure.......... I'm really puzzled. Some graphics programs, and I cannot remember whether GC does this, will do cropping without recompressing the image, so you do not lose any quality. Ofc, as soon as you do anything else to the image, recompressing is going to happen.

[eligurwayne]

Is this .jpg and does the quality make a difference?Usually as Thorsten said one saves at 70 to 80 percent. On majority of images it is fine. Saves lots of space.

[Carl von Einem]

If I remember the beginning of this thread correctly the aim of the batch process was to prepare a number of images for some different process, e.g. some multimedia project or rendering. If that's the case I wouldn't care for (cheap) size on disk but for easily processible frames. I'd make sure to not alter colors (like JPEG recompression would actually do) and discuss with the people who are working with the output what kind of files they prefer. Maybe a stack of files with identical size (in pixels) in an uncompressed (saves time opening when processing larger amounts of images) file format like plain TIFF. David Morrison davidmorrisonlist@gmail.com [gcmac] wrote on 03.03.15 01:34: >> >> >> I looked at the resolution and both the original and the cropped >> image are 72 pixel/in. So I don't see how that could result in a >> much larger file size. >> >> Out of curiosity, I then tried "Save As..." for one of the original >> images without doing any cropping. The options were set to >> JPEG/JFIF, 100% quality, and I clicked on each of the codec options >> with "show file size" on. All 3 yield a larger file for the copy >> than for the original, with the smallest difference being for >> progressive codec. I also used the default subsampling -- is that >> what is adding to the file size? The image size is 1419x1200 to >> start with, if that matters. >> >> Finally, I tried the same test with a previously cropped and saved >> image. This time the new (but supposedly unaltered) file is smaller >> than the original. Go figure.......... I'm really puzzled. > > Some graphics programs, and I cannot remember whether GC does this, > will do cropping without recompressing the image, so you do not lose > any quality. Ofc, as soon as you do anything else to the image, > recompressing is going to happen. > > > > ------------------------------------ > Posted by: David Morrison <davidmorrisonlist@gmail.com> > ------------------------------------ > > > ------------------------------------ > > Yahoo Groups Links > > >