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I am looping through a directory and copying all files. Right now I am doing string.EndsWith checks for ".jpg" or ".png", etc . .

Is there any more elegant way of determining if a file is an image (any image type) without the hacky check like above?


Check the file for a known header. (Info from link also mentioned in this answer)

The first eight bytes of a PNG file always contain the following (decimal) values: 137 80 78 71 13 10 26 10

check if file is an image file - Wrox, But remember, I may even rename the .doc file as .jpg, which you can't check if that is a real valid image. Cheers! - Vijay  Determine if uploaded file is image (any format) on MVC. Ask Question Asked 7 years, 10 months ago. Active 1 year ago. determine if file is an image. 7.


Check out System.IO.Path.GetExtension

Here is a quick sample.

public static readonly List<string> ImageExtensions = new List<string> { ".JPG", ".JPE", ".BMP", ".GIF", ".PNG" };

private void button_Click(object sender, RoutedEventArgs e)
{
    var folder = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
    var files = Directory.GetFiles(folder);
    foreach(var f in files)
    {
        if (ImageExtensions.Contains(Path.GetExtension(f).ToUpperInvariant()))
        {
            // process image
        }
    }
}

JavaScript check if file is image - Step by Step tutorial, When dealing with files in JavaScript, you may want to check whether or not a file is an image. This tutorial will show how to JavaScript check if  Using file extension and getimagesize function to detect if uploaded file has right format is just the entry level check and it can simply bypass by uploading a file with true extension and some byte of an image header but wrong content.


This will look at the first few bytes of a file and determine whether it is an image.

using System.Collections.Generic;
using System.IO;
using System.Linq;

public static class Extension
{
    public static bool IsImage(this Stream stream)
    {
        stream.Seek(0, SeekOrigin.Begin);

        List<string> jpg = new List<string> { "FF", "D8" };
        List<string> bmp = new List<string> { "42", "4D" };
        List<string> gif = new List<string> { "47", "49", "46" };
        List<string> png = new List<string> { "89", "50", "4E", "47", "0D", "0A", "1A", "0A" };
        List<List<string>> imgTypes = new List<List<string>> { jpg, bmp, gif, png };

        List<string> bytesIterated = new List<string>();

        for (int i = 0; i < 8; i++)
        {
            string bit = stream.ReadByte().ToString("X2");
            bytesIterated.Add(bit);

            bool isImage = imgTypes.Any(img => !img.Except(bytesIterated).Any());
            if (isImage)
            {
                return true;
            }
        }

        return false;
    }
}

Edit

I've made a few changes to the above to allow you to add your own images if you needed to, also removed collections which weren't necessary to begin with. I also added an overload accepting an out parameter of type string, setting the value to the type of image the stream is composed of.

public static class Extension
{
    static Extension()
    {
        ImageTypes = new Dictionary<string, string>();
        ImageTypes.Add("FFD8","jpg");
        ImageTypes.Add("424D","bmp");
        ImageTypes.Add("474946","gif");
        ImageTypes.Add("89504E470D0A1A0A","png");
    }

    /// <summary>
    ///     <para> Registers a hexadecimal value used for a given image type </para>
    ///     <param name="imageType"> The type of image, example: "png" </param>
    ///     <param name="uniqueHeaderAsHex"> The type of image, example: "89504E470D0A1A0A" </param>
    /// </summary>
    public static void RegisterImageHeaderSignature(string imageType, string uniqueHeaderAsHex)
    {
        Regex validator = new Regex(@"^[A-F0-9]+$", RegexOptions.CultureInvariant);

        uniqueHeaderAsHex = uniqueHeaderAsHex.Replace(" ", "");

        if (string.IsNullOrWhiteSpace(imageType))         throw new ArgumentNullException("imageType");
        if (string.IsNullOrWhiteSpace(uniqueHeaderAsHex)) throw new ArgumentNullException("uniqueHeaderAsHex");
        if (uniqueHeaderAsHex.Length % 2 != 0)            throw new ArgumentException    ("Hexadecimal value is invalid");
        if (!validator.IsMatch(uniqueHeaderAsHex))        throw new ArgumentException    ("Hexadecimal value is invalid");

        ImageTypes.Add(uniqueHeaderAsHex, imageType);
    }

    private static Dictionary<string, string> ImageTypes;

    public static bool IsImage(this Stream stream)
    {
        string imageType;
        return stream.IsImage(out imageType);
    }

    public static bool IsImage(this Stream stream, out string imageType)
    {
        stream.Seek(0, SeekOrigin.Begin);
        StringBuilder builder = new StringBuilder();
        int largestByteHeader = ImageTypes.Max(img => img.Value.Length);

        for (int i = 0; i < largestByteHeader; i++)
        {
            string bit = stream.ReadByte().ToString("X2");
            builder.Append(bit);

            string builtHex = builder.ToString();
            bool isImage = ImageTypes.Keys.Any(img => img == builtHex);
            if (isImage)
            {
                imageType = ImageTypes[builder.ToString()];
                return true;
            }
        }
        imageType = null;
        return false;
    }
}

How can I tell if a file is an image of some type?, A customer wanted to know if there is some standard way of determining from the full path to a file whether it is a photo or image. They are  The getimagesize function of php provides lot of information about an image file , including its type. The type can be used to check if the file is a valid image file or not. The type can be used to check if the file is a valid image file or not.


C# Is file an image and get its type · GitHub, Includes a mini-program for checking and fixing files that have no extension. // Only checks for the most common types. // If you create a better version, please  On Windows 8, you can natively mount the disc image to a virtual drive to view its contents. Open the ISO file and see if it contains a folder called “BOOT”. This gives a faint idea that the ISO image is supposed to be bootable, although it doesn’t guarantee as the file could be a data disc burned directly from the hard disk.


We can use Image and graphics classes from namespace System.Drawing; to do our job. If the code works without error it is an image, else it is not. That is let the DotNet framework do the job for us. The code -

public string CheckFile(file)
{
    string result="";
    try
    {
        System.Drawing.Image imgInput = System.Drawing.Image.FromFile(file);
        System.Drawing.Graphics gInput = System.Drawing.Graphics.fromimage(imgInput);  
        Imaging.ImageFormat thisFormat = imgInput.RawFormat;   
        result="It is image";        
    }
    catch(Exception ex)
    {
        result="It is not image"; 
    }
    return result;
}

sindresorhus/is-image: Check if a file path is an image, Check if a file path is an image. Contribute to sindresorhus/is-image development by creating an account on GitHub. To find out how many pixels are in an image, select the image in Explorer (Windows) or Finder (Mac) and its dimensions will be displayed in pixels. You can then divide the number of pixels by 300 to see the maximum size the image can be used at for printing. Using Photoshop to determine maximum printing size


How to check if an uploaded file is an image in Laravel, all extension type for images. $isImage = request(“fieldName”)->​getClientOriginalExtension(); // the extension of file . if (in_array($isImage , $​extension){. Our form will send the data to validate_image_upload.php. Here, the script will check the type of validation. If the file is validated the user will see a successful submission message and the file will be moved in the specified image folder.


How to Check if a File is a Valid Image with Python, jpeg / jpg; bmp; png; webp; exr. Here is how you would use it imghdr to detect the image type of a file:. How can I detect if a PDF needs to be OCRd? You just received 1000 PDFs from the other side which are a mix of PDFs created from Office applications and scans. Some of the documents might have been OCRd and some not.


Detect Image File Types Through Byte Arrays, Did you know that certain image file types when read as a byte array have the same collection of bytes every time? Instead of checking for an  exif_imagetype() reads the first bytes of an image and checks its signature. exif_imagetype() can be used to avoid calls to other exif functions with unsupported file types or in conjunction with $_SERVER['HTTP_ACCEPT'] to check whether or not the viewer is able to see a specific image in the browser.