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32

Because they are way better at compressing pictures that have lots of colours and irregular shapes, like photographs. Have you tried the same epxeriment you did, but then with a photograph? The .png is most probably going to be noticeably bigger than any .jpg, regardless of the .jpg's compression factor. Example: .png picture, 110k. .jpg at 100% ...


19

In short, Facebook is converting your image to the JPEG/JPG format (Join Photographic Experts Group). There seems to be no current way to upload images to use as a profile picture or to your photo album which Facebook will not convert to JPEG. ...a commonly used method of lossy compression for digital photography (image). The degree of compression can ...


18

Any time a format isn't available in the Save As dialog, it means that format is invalid for the document in the state it's in. There's no such thing (as Lese and cwedge point out), as a 32-bit (or 16-bit) jpeg, nor a duotone, Lab or 1-bit bitmap jpeg. Photoshop versions prior to CS5 would simply not show jpeg as an available option for 16-bit images, which ...


11

JPEG has backing from the photographic industry and predates PNG by a half-dozen years or so, while PNG was designed as a replacement for GIF, which was rather zealously protected by CompuServe. People were sued for using GIFs on their websites, for example, simply because they didn't use a program that was licensed by CompuServe to make those images. From ...


9

Why low quality JPG saved as high quality in Photoshop increases the file size? If you have a low quality JPEG which you open and reā€“save with 100% quality (or 0% compression) in any image editing software, the output will be bigger in size than the source. In order to understand this, it is good to take a crash course on JPEG. JPEG compression isn't ...


8

Some compression-algorithms change the image to gain a better compression-ration - that are lossy algorithms/image formats. Most notably here is JPEG. Some keep all image information, these are called lossless. Lossless compression produces bigger files, but you have no changes to your graphic. Common lossless image formats are PNG, GIF or TIFF. As most of ...


8

Although the question was asked about Adobe Photoshop, the behavior is due to the lossy JPEG format and would be similar with any image editor. Cropping a JPEG can make it less compressible, especially when the x and y offsets of the cropped area are odd numbers. This causes a re-subsampling of the color channels that can make the cropped image more complex ...


7

Here is an article on exactly your problem. Been having this problem as well. Hope this helps! Facebook uses a low quality jpg compression so any solid colors end up looking heavily pixelated. Solution is to add images at double the size with noise.


7

This is an outdated piece of advice related to using images in older layout programs that were not Photoshop-aware. It has no relevance to Save for Web. A jpeg is a flat file, and Photoshop takes care of the flattening (and conversion to sRGB for web use) automatically. In general, practice non-destructive editing: never flatten a PSD, never change original ...


7

Having the same problem with a white text on a solid red background. My solution was to replace the solid red by a gradient of to reds. Afterwards I also added a Noise filter (or grain filter (7) in the filter gallery) in Photoshop. The improvement was very noticeable and the result was perfect. In attachment you can see the original and the finished result. ...


7

My first, second and third answers to this question would be "Find a different printer, because the one you have is incompetent." There is no grande format equipment made that requires jpeg as input. Typical spec, this one from the Fuji website: Formats All popular desktop formats including PostScript 3, EPS, TIFF, PDF, both RGB and CMYK color ...


7

There is no simple answer - each compression event dumps some data, it tends to dump less with subsequent saves as most of the disposable data has already been disposed of. Factors include the compression level, the size of the image, it's content, your personal threshold of "noticeable" and the quality of your monitor.


6

When saving images as .jpeg you always lose information. The dialog basically asks you how much information you would like to lose in favor of smaller size on disk (1 = most loss, 100 = least loss). There is no way to tell what you originally selected and the only use would be to have a history of your workflow because this loss is irrecoverably applied to ...


6

I've seen a video featuring this. I'm not sure what it was anymore, but check out these 3 videos (from YouTube and Vimeo): (The images aren't hyperlinked. Instead, there are linked texts at the bottom of each.) 1-Jpeg degradation by Connecticut State Library 2-JPG artifact test 1000 saves by Martin Flucka 3-Generation Loss by hadto This last one by ...


6

Something not mentioned in great detail is the way these compression algorithms work. JPEG is targeted directly at photographs where slight changes in pixel color are not noticed. PNG is targeted more for fabricated images that contain large areas of a single color where is compression is taken full advantage of like in your example of a huge all white photo ...


6

If you really are sensitive to the quality then you should avoid jpeg. You allready lost quality when the original image was saved as jpeg, nothing brings this quality back. In general you should avoid saving your documents out to jpeg unless your shipping the images off somewhere in their final form. Its hard to say wether the quality suffers much at all, ...


5

What you're observing is not a clipping mask, per se. Jpeg has no transparency and no concept of clipping or masking. Jpeg does have several metadata sections, and many programs will happily store extra information in there. Photoshop stores paths, as you've noticed, and guides. To replicate this, create a new file and add some paths and guides. Then ...


5

Apparently it is a relic from the days of experimentation in the Adobe labs. It is not recommended to use higher than 10 on that scale, it may actually lower the quality of the image or substantially bloat the file size. It would be a welcome change if Adobe removed that experimental extension of the scale.


4

You probably have the color mode set to 32-bit per channel, but it's hard to tell without knowing what the 5 displayed formats are. If that is the case: first rasterize the layers, then change Image|Mode from 32 bits per channel to 16 bits per channel. Save As then includes JPEG but with a warning that you can ignore; just save it.


4

Command line is quicker. Install Imagemagick. One file: convert -transparent white whatever.jpg whatever.png More files: Put together a bash script file: for img in *.jpg; do filename=${img%.*} convert -transparent white "$filename.jpg" "$filename.png" done Run it and then you will be done. Note that the above will add transparency to everything ...


4

For me... with no transparency.. whichever is smaller (kb). Save for Web in Adobe apps allows you to switch between formats to compare resulting file sizes. I simply switch between PNG24 and JPG to compare the resulting sizes. I start with JPG medium (30) and check quality. Then compare to the PNG24 size. If JPG 30 is smaller.... I start stepping up by ...


4

The rule of thumb is to use JPEG for photos, and PNG for graphics. Of course, there are instances where this rule doesn't apply, but usually this is the best choice. The advantage of JPEG is that it can compress large, detailed images to workable file sizes. PNG works better for images that have straight lines and geometric shapes (lines that shouldn't ...


4

The reason why your images look different is because of the compression you applied to the second one. The higher the compression, the more the quality degrades. JPEG is a lossy compression format, meaning there is loss of image information during the compression (a sacrifice needed to make the file smaller). For example, this is the same image saved with ...


4

Is that a good idea, in theory? Sure. If yes, is there a program or algorithm that can do the image split and the compression with the following goals: I don't now that you need that. I'd build the image in a program that can handle layers (such as Photoshop). Hide the top layer and export as a highly compressed JPG. Hide the bottom layer and ...


4

1) The facts The reason you have a higher settings than 10/12 is becouse 12/12 is a higher setting. Here are some compression tests following my methodology explained here (In spanish, please use google translate if needed): http://otake.com.mx/Apuntes/PruebasDeCompresion2/1-CompresionJpgProceso.htm a) Using the compression (save as) 12/12 you have a ...


3

Here on Adobe forums is a same problem with successful results: http://forums.adobe.com/message/4271028 Maybe the APP14 tag is not correct? Theres more to APP14 tags than it just being there. On JPEG tags: http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe JPEG Adobe Tags The "Adobe" APP14 segment stores image encoding information for ...


3

My approach would be to use Select > Color Range: Eyedropper a clean area of the yellow to make it the foreground color. Be sure to set the sampling to 3x3 or 5x5, not single pixel. Choose Select > Color Range and click the "+" icon in the dialog. Work with the image until all the icon pixels are selected but none of the background (should be easy). ...


3

File >> scripts >> Load files into stack Browse for your 450 images, select them all, and press open. This will take a long time! When it's finished the process go to: image >> canvas size Change the width of the document to your desired amount. Now align the first frame to the far left of the canvas, and the last frame to the far right. Select all ...


3

If you use GIMP, I can suggest this tutorial: Perfect masking using a highpass guide. I had very good results with complex images by following it.


3

Quick and easy workaround is to Save a Copy. Hold down Option/Alt when you choose Save As. If there's something about the image specifically preventing a format choice, the save as copy will remove that aspect of the image. Although.... There are very few times when you actually want to save as a jpg and not use Save for Web. Be aware, jpg is a lossy format ...



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