jpeg

Efficient JPEG Image Resizing in PHP

What's the most efficient way to resize large images in PHP? I'm currently using the GD function imagecopyresampled to take high resolution images, and cleanly resize them down to a size for web viewing (roughly 700 pixels wide by 700 pixels tall). This works great on small (under 2 MB) photos and the entire resize operation takes less...

How to compress JPEG images with ASP on Windows CE

The ASP page gets data uses that to draw a graph, I then need to save the image created to JPEG to be displayed on the browser and also used in PDF and other format. What is the best way to compress the image? I am currently porting a JPEG compression library to ASP but I think it will be too slow on this ARM device running Windows CE 6....

Is there a quality, file-size, or other benefit to JPEG sizes being multiples of 8px or 16px?

The JPEG compression encoding process splits a given image into blocks of 8x8 pixels, working with these blocks in future lossy and lossless compressions. [source] It is also mentioned that if the image is a multiple 1MCU block (defined as a Minimum Coded Unit, 'usually 16 pixels in both directions') that lossless alterations to a JPEG ...

Fastest way to determine image resolution and file type in PHP or Unix command line?

I'm currently using ImageMagick to determine the resolution of images uploaded to the website. By calling ImageMagick's "identify" on the command line it takes about 0.42 seconds to determine a 1MB JPEG's resolution along with the fact that it's a JPEG. I find that a bit slow. Using the Imagick PHP library is even slower as it attemps t...

How do you place EXIF tags into a JPG, having the raw jpeg buffer in C++?

I am having a bit of a problem. I get a RAW char* buffer from a camera and I need to add this tags before I can save it to disk. Writing the file to disk and reading it back again is not an option, as this will happen thousands of times. The buffer data I receive from the camera does not contain any EXIF information, apart from the Wid...

Why does IE7 specify a mime-type of image/pjpeg rather than just image/jpeg?

When uploading a file (jpeg) via a form in IE7 I am seeing a mime-type of "image/pjpeg" instead of "image/jpeg" (as I see in Firefox or similar). It's easy enough to work around this problem, but I'm just wondering why IE7 is behaving differently in this case? ...

Get the resolution of a jpeg image using C# and the .NET Environment?

Our clients will be uploading images to be printed on their documents and we have been asked to come up with a way to get the resolution of the image in order to warn them if the image has too low of a resolution and will look pixalated in the end-product If it comes to it we could also go with the dimensions if anyone knows how to get ...

Create a JPEG in PHP w/o creating a file?

Here's my situation - I want to create a resized jpeg image from a user uploaded image, and then send it to S3 for storage, but am looking to avoid writing the resized jpeg to the disk and then reloading it for the S3 request. Is there a way to do this completely in memory, with the image data jpeg formatted, saved in a variable? Thank...

Automatic image format detection in PHP

I am looking for a way to take a user uploaded image that is currently put in a temporary location ex: /tmp/jkhjkh78 and create a php image from it, autodetecting the format. Is there a more clever way to do this than a bunch of try/catching with imagefromjpeg, imagefrompng, etc? ...

Efficiently detect corrupted jpeg file?

Is there an efficient way of detecting if a jpeg file is corrupted? Background info:   solutions needs to work from within a php script   the jpeg files are on disk   manual checking is no option (user uploaded data) I know that imagecreatefromjpeg(string $filename); can do it. But it is quite slow at doing so. Does anybody know a...

What is the difference between: image/x-citrix-pjpeg and image/pjpeg

Some files are uploaded with a reported MIME type: image/x-citrix-pjpeg They are valid jpeg files and I accept them as such. I was wondering however: why is the MIME type different? Is there any difference in the format? or was this mimetype invented by some light bulb at citrix for no apparent reason? ...

Print JPEG File Using JSP

Hello all, Is there a JSP script I can run to point to a JPEG file on the local filesystem to be printed to the Windows default printer? Thanks. Edit: I have the file on my server already. How would I load the file into a browser to run window.print()? Thanks ...

Write dpi metadata to a jpeg image in Java

I am trying to programatically set the dpi metadata of an jpeg image in Java. The source of the image is a scanner, so I get the horizontal/vertical resolution from TWAIN, along with the image raw data. I'd like to save this info for better print results. Here's the code I have so far. It saves the raw image (byteArray) to a JPEG file, ...

JPEG -> more compressed JPEG — is it worth it?

I'm working on a site that involves displaying a ton of product images from a variety of online retailers. Since most of the page weight is in the images, I thought it'd be worth looking into techniques for trimming down the file size a bit more. The images are already JPEGs. I know PNGs have a lot of extra cruft that can balloon the f...

JPEG or other lossy image compression library needed

I've incorporated LIBPNG and ZLIB into my C software for a microcontroller project due to their nicely liberal license which permits such use without requiring me to disclose any of my code (it's very similar to BSD/MIT/APACHE, but with no attribution requirement). I'd like to look at using lossy image compression to save memory. The J...

How to get color space of a jpeg/tiff in java?

Hi, the title sums it up really. Using the standalone exiftool program to dump all image metadata to a console I can see a line Color Space Data : RGB It looks like this is taken from the ICC-header I want to get the same data programatically in java. I've tried the drew noakes library and the Sanselan library, but neither give me a val...

WPF: TIFF images with JPEG compression?

I have a large number of TIFF images that I’d need to use in a WPF program (.NET 3.5 SP1 specifically and using C#). Half of the TIFF files contain color images encoded using JPEG compression and they don’t work with WPF. The “Microsoft Office Document Imaging” application handles the files fine. As Windows itself doesn’t really like the...

Convert a multi page Tiff to jpeg in .Net1.1

Is there a way to convert a multi page Tiff file to a jpeg file in VB.net 1.1. I've tried to convert it with the standard Bitmap.Save() method but it only converts the first page. ...

Get dimensions of JPEG in C++

Hi, I need to get at the image dimensions of a JPEG in C++. I'm looking for either a fairly simple way to do it, or a smallish library that provides that functionality. I'm working in C++ on OpenVMS, so any external libraries may have to be adapted to compile on our systems - so please don't post me links to big, closed source libraries...

C# read a JPEG from file and store as an Image.

How can I read a JPEG on my filesystem and store it as a System.Drawing.Image within my C# code? ...