![]() ![]() Step 2: Launch the application and add the images you want to resize by clicking on the “Add” or “Input” button. Step 1: Download and install a batch image resizer, such as FastStone Photo Resizer or XnConvert. ![]() Step 5: Save the resized image using the “Save As” or “Export” option, and choose a suitable file format, such as JPEG or PNG. Ensure that the “Maintain Aspect Ratio” option is enabled to avoid distortion. Step 4: Adjust the image dimensions by either entering new values or using the percentage scale. Step 3: Navigate to the “Image” menu and select “Image Size” or “Scale Image.” Step 2: Open the image you want to reduce in size. Step 1: Open your preferred photo editing software, such as Adobe Photoshop or GIMP. Optimize Images Using Photo Editing Software Once the process is complete, click on the “Download” button to save the compressed image to your device.Ģ. Step 3: The tool will automatically compress the image. Step 2: Click on the “Upload” or “Select Files” button to choose the image you want to compress. In addition, if I really wanted to economise on size and processing time the jpg option would be a huge leap further.Step 1: Open your preferred web browser and navigate to an online image compression tool, such as TinyPNG or Compress JPEG. Here processing time becomes significantly longer the more one compresses.įor comparison, saving the photo as a jpg at 80% with the 'slowest = best' algorithm takes just 2 seconds and results in a file of 975 kB - less than 10% of the PNG filesize.įor me, the preferred default would be level 3 = 11,000 kB / 6 seconds rather than level 6 = 10,200 kB / 12 seconds - it halves the time, while the resulting file is (only) 8% larger, which is not much considering download speeds available over the internet and how the price for huge capacity harddisks has fallen to the order of 10 cents per GigaByte. ![]() Repeated the exercise with a photo, the original jpg is 3450 x 2600 pixels, saved by camera as 4000 kB PNG level 0 = 26,300 kB / 3 seconds, level 1 = 11,700 kB / 4 seconds, level 9 = 9,900 kB / 38 seconds and level 5 = 10,400 kB / 9 seconds. The file is too small to notice any difference in processing time. The original file at compression 0 is 2600 kB, level 1 reduces that to 137 kB, the default level 6 to 115 and the top level 9 to 112 kB. Today saved a black on white diagram (1150 x 775 pixels) - with some halftone edges - and found that contrary to posts dating from five years ago the file now indeed gets smaller with each higher compression level. (Some achieve the smallest size at level 4 and then remain at that size from 5-9, some continually get smaller until they reach level 9, but none make that sudden jump that the photographic images do.) Simpler, graphic-type images follow the expected pattern and achieve their smallest size at level 9. Complex, photographic-type images achieve the smallest size at a compression level of 3, then jump at level 4. I will have to run some more experiments with different images and differe programs and see what happens.ĮDIT: I just ran some tests, and it's related to the specific image. Photoshop for instance, is known to create bloated PNGs), the image itself, or if this always holds true. I wonder if it's related to xnview (not all programs handle PNGs the same. It made a big jump in size from 3 to 4, and never went back down quite as far, even up to level 9. I just ran a quick test to compare file sizes with different compression settings, and found that level 3 was actually smallest. (0 level PNGs are slightly larger than even the bloated BMPs, because they also have no compression, plus they have some extra headers.) Level 6 is the standard/default setting, 9 gives slightly smaller files, but can be noticeably slower (especially on large images). You should never use 0 compression, as it does not decrease compression time at all vs a setting of 1 (technically, it would have to, but it would only be in the range of about 1 bilisecond), yet results in a massive file. These PNGs are reduced to 256 colors before saving (just like GIFs), but are otherwise completely lossless (again, just like GIFs).Ģ) The compression setting in PNG is merely a tradeoff between filesize and speed. The only PNGs that have any data loss are 256 color/indexed PNGs. All PNGs are compressed with the zlib deflate format, which is very closely related to ZIP, and is completely lossless. There are a few people tinkering with the idea of lossy PNGs, but even these actually result in lossless files, they just apply some lossy filters before saving. ![]()
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