Change file size of image gimp bytes
It packed the data in the file and decided to take a close lookĪt how the profile is expressed in terms of the ICC fileįormat, and ended up using the ICC writing code and transform Treated as sRGB, having implemented reading and writing of the The tiny sRGB ICC profile which calls itself "c2" in its ownĭescription is considered by babl similar enough to sRGB to be Rather than sRGB, probably yielding worst results on wide-gamutĭisplays, there are other ways of more tersely specifying sRGB for a JPG through fields of exif tags - but that is beyond the scope of this article] Treat untagged images as if they were in the display-space, [Some versions of some web browsers apparently Precise enough for display of 8bpc JPEGs images and SRGB ICC profile from 2012, which encodes the sRGB Small error bound equal to standard RGB spaces to be exactlyĪfter implementing the matching I stumbled across facebook's Point and fixed point representations used in the ICC profileīabl upgrades loaded ICC RGB spaces that are within a Slightly different starting points, and different floating SRGB ICC profiles out there, resulting from Babl also has theĪbility to write such information back out as an ICC This information can be provided directly to babl - or babl canĮxtract the information from an ICC profile. The pixels to GEGL and GIMP's pixel conversion library, babl. I've been addding the ability to specify the colorimetricĬharacteristics of the RGB color space used to store colors in Profiles are widely supported (like the web). Handling of 8bpc images files in environments where ICC v2 ICC v2, sRGB equivalent profile, useful for ensuring consistent To know whether such a solution is reasonable, we have to know the true numbers of your problem.Īlso, if you are really going to throw away the information permanently, you are almost certainly better off using JPEG compression, which is designed to lose information reasonably gracefully.This page is about the size and precision optimizations of (The examples are netpbm/ pbmplus, which I have always found easier to understand than ImageMagick.) If that's not enough you can toss a ppmquant in the middle (on the small image) to reduce the number of colors. pngtopng big.png | pnmscale -reduce 6 | pnmscale 6 | pnmtopng > big.png If you get unlucky the savings will be more like 6. If you get lucky, you'll reduce image size by a factor of 36. Meanwhile, the "cheap and cheerful" approach I would try would be as follows: scale the image down by a factor of 6, then scale it back up by a factor of 6, then run it through PNG compression. Your example is troublesome because a 30MB image at 800圆00 resolution is storing 500 bits per pixel. Just keep playing with the quality value until you get a suitable output. From the docs: $magick> convert input.png -quality 75 output.jpg Read through the docs, and start experimenting!ĮDIT: Looks like it should, indeed, be pretty easy with ImageMagick.
Again, the quality / size of the output will depend on the type of image.įinally, while I have not used ImageMagick in a little while, I'm almost certain there are options to re-compress an image using a specific quality factor. If not, JPEG almost certainly could- JPEG compression ratios on the order of 10:1 are not uncommon. Depending on the type of image, the PNG compression may very well provide that level of compression. Therefore, you only need a 1.4:1 compression ratio to get the image down to 1MB. (I would be very surprised to see a 30MB file at those smallish dimensions.) In fact, even uncompressed, the image would only be around 1.4MB: 800 pixels * 600 pixels * 3 Bytes / color = 1,440,000 Bytes = 1.4MB However, at 800圆00, it likely will be very easy to get a JPEG down under 1MB. (PNG, on the other hand, has the opposite behavior- it's best for logos, etc.) It does not do as well for logos, screen shots, or other images with "sharp" transitions from light to dark. JPEG does best for "true life" images, such as pictures from cameras. Obviously, depending on the image, the loss of visual quality may be substantial. All of this can be done without changing the image resolution. JPEG has a settable "quality" factor- you could simply keep reducing the quality factor until you got an image that was small enough. PNG is not a lossy image format, so you would likely need to convert the image into another format- most likely JPEG.