29

I used ImageMagick on Ubuntu to resize those big pictures. convert -resize 10% source.jpg dest.jpg It took awhile, but worked with 1 GByte of RAM, the tool created a 4.7 Gbyte swap-like file for itself. More information is on AskUbuntu.


12

You have to convert them to some other format, but that format doesn't have to be JPEG. For example, you could save the files as TIFF or PNG instead of JPEG. RAW files are data read more or less straight from the sensor, so it doesn't make sense to "resize" such files. You have to instead process them into a useable image format, which you can then ...


12

I have found the free waifu2x very good for upsizing images. You can try an online demo. It uses "Deep Convolutional Neural Networks" to predict what the missing image data should be. It works better for line art, but is definitely acceptable for photos.


11

First of all you need to use a good resize algorithm for that case. Lanczos, or Photoshop's Bicucbic optimized for reduction. And then to make for better contrast around the letters you can use some output sharpening. Secondly, there is a minimum resolution you can use to render the fine letters. The book is a perfect example because of the different fonts ...


11

Any photo you're never going to use again is taking up "unnecessary" space, and frankly no matter what happens to image processing technologies in the future, you're probably not going to go back and reprocess some low quality photos from 10 years ago. On the other hand, disk space is cheap (unless you're Google, Amazon, etc). Very roughly, my SLR has a ...


11

Have a DOG sniff out blur in the photos. If you're going to be penalizing for digitally enlarged photos, you might as well penalize for out-of-focus photos too. The blurred edges and details in both cause the same bad experience for viewers, regardless of whether it is caused by a small original or poor focus. What you want to do is detect blur, which is an ...


9

Theoretically, most image formats could be downscaled progressively, without loading the entire image into memory, however I do not know any tools that really implement such feature, except for JPEG: it is special in that you can not only downscale without loading full resolution, but also downscale without decoding full resolution, thanks to the creative ...


8

You could use dcraw to convert the raw image data to a "raw" tiff file that only contains the raw image data. You do that by giving the command "dcraw -D filename". This will produce a tiff file without any demosaicing or scaling. Such a tiff file is then smaller than an ordinary tiff file because each pixel is then only either a "red", "green" or a "blue" ...


7

You can also try using Picture Resizer on Windows (I love this tool) You simply drag and drop the picture on this simple EXE It is especially useful if you have many pictures to convert as you can do many at a time. All the config is done through the naming of the EXE which is brilliant IMO I have never tried it with huge file though.


7

Use a copy of your file, do not resize your original photo. You can use this free program: http://www.gimp.org/ Using Gimp: Open your file. Use the rectangle select tool. (Define some initial dimensions to set the proportion you need) Move it, scale if from the corners to mantain the proportion and frame your image. Menu > Image > Crop to selection. ...


7

The "ImageOptim" tool pulls together a bunch of other things, and in the case of JPEG files, the relevant thing is the MozJPEG optimizing encoder. If you use this encoder and then resize and save with a different encoder, you will lose the benefit. Saving with the optimizer needs to be the last step. Also worth noting: if you're starting with a JPEG and ...


6

Every digital image has a specific size: the width and height in pixels. The amount of information depends on that. In digital image files, the number of pixels per inch is just a hint. It indicates a proportion that should be used for calculating the actual size of the image when printed. If you have an image of 1000x1000 pixels and you print it at 100ppi,...


6

Select the RAW photos, then do an Export. In the Export Location section, choose Export To: Same folder as original photo. Check the Add to This Catalog Checkbox. Select the file output options you want for the new images. Export the images. At this point the JPG's will be imported into the same folder, and your RAW files should still be selected, ...


5

To understand why you can't do this, it's helpful to understand how RAW works. A RAW doesn't actually contain colored pixels, it's a single channel ("gray scale") image representing alternating red blue and green pixels called a Bayer pattern. To actually get the "actual" pixels, you have to extrapolate from each of the pixels neighbors using a complex ...


5

Depends. If you just resized the image in Word, it probably only changed the display scaling and didn't actually resize the image. If you did actually resize the image, though, this is an operation which inherently discards data. Once that information is gone, there's no way to get it back, because there's no where to get it back from.


4

Although it's very clear in the sharp lines of letters, this actually happens to all detail when a digital image is resized. The algorithms used to shrink an image interpolate information from the surrounding pixels. This prevents artifacts like jaggy lines (aliasing, in computer graphics terminology), but introduces blur. The easiest approach is to run a ...


4

Do the math. If you really need 300 DPI, then at most your picture can be (2500 pixels)/(300 pixels/inch) = 8.3 inches wide. If you want bigger than that you either can't, or you have to relax your resolution requirements. 200 DPI might still be good enough for something hand-held, for example. The resolution the picture needs to have depends on viewing ...


3

Yes. Changing the size of the image without resampling is called "cropping" — the pixels in the new image are identical to the pixels in the old image, they just live in a differently-sized space. You want to map the old pixels into the new space, and that requires resampling whether the new space is larger or smaller than the old space. The reason why ...


3

If you have a circle made by putting a black spot in the center spot on each side of a 3 by 3 grid, what do you get if you take a photo of it that uses 300 spots? You get a square on the center of each side using a bunch of pixels to make each square. You can't increase the amount of information in an image if there is no information to capture. Your ...


3

You can take a photo that's arbitrarily detailed with respect to the dots that exist in your subject (at 300dpi), but you can't find new dots where there are none in the print now. Perfect resize (and other resizing algorithms) will attempt to deduce what the "dots between the dots" should look like base on interpolation algorithms. Like most photo ...


3

The reasons for doing sharpening as the final step are primarily because the intended output media determines what sort of sharpening is applied, the idea is that you are compensating for any softening that will occur during printing, or resizing for the web. However, sharpening is more or less a cumulative effect. This means that if you sharpen the eyes as ...


3

Based on junkyardsparkle's pre-processing (I cropped the sample in order to fit 1:1 /when upscaled/ to page) I've tried to employ 10 various upscaling methods (including very exotic ones) to find out which one would cope with the weird Epson PhotoPC 600 pixel rendering best. The samples are upscaled to 200% as requested with no further post-processing. ...


3

Perfect Resize (formerly Genuine Fractals) is usually considered as one of the best available upsampling tools for photography. It is worth trying. Another, actually the opposite approach might be to use strictly multiples of the original size (like 2x = 640x480) and use the simplest thing - nearest neighbor algorithm that will just make the pixels look ...


3

Say a 2000 by 3000px photo is reduced to 1000 by 2000px. Would the smaller image appear to be sharper? No. Sharpness is limited by the display's resolution -- the number of pixels per inch. If you want to increase the make the displayed image seem sharper, you need to increase the display resolution. You can (sort of) do that not by making the image smaller,...


3

You will not get the same result at all. When you start with your 2000x2000 pixel image you have some scene or subject in it. If you crop it down to 500x500 pixels then you will only have 1/16th of the subject in it. However if you have a 500x500 with the same but lower resolution content, you will have an entire subject. What you can do instead is scale ...


3

Short answer: you can't do it with just one image. Long[er] answer: to realistically simulate distance change, you need either multiple images taken from multiple different subject distances or to actually geometrically distort the original image. The reason behind this is that physically changing the distance of your subject changes your perspective of it. ...


2

Irfanview can do this but takes a bit of setting up. Use the Batch conversion option. Choose "PNG" as your output format. Click on the "options" button next to the output format and choose the compression that you want and click OK Tick the box that says "Use advanced option" then click the "advanced" button You'll see this window Set up the resize with ...


2

The best techniques for enlargement of a pictorial scene involve vectorization and/or quantization in the frequency spectrum. One successful approach involves converting the image to a series of fractals. The fractal image is then resized. Some software, including plugins for photoshop and gIMP will convert your raster graphic to fractals, resize it, and ...


2

Based on this research paper, "Super-Resolution From a Single Image", from 2009 I found an implementation called QE SuperResolution which is an ok implementation. The examples on the above page are just stunning (click the "SR" button to see the super-resolution version), and I doubt you could find anything better than that as of 2015.


2

If your image is 240px * 240px at 240dpi, and you change the resolution in photoshop to 72dpi, the image is still 240px * 240px and the quality isn't changed. It is just a reference for if the image is to be printed. If you're using an image onscreen you can ignore the dpi, it will only ever display the number of pixels. I've found the best way to export ...


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