Imagefrom.File(). Out of memory exception

Question

I am trying to load about 60 pictures in a list. Each picture is about 1MB. For 20 pictures no problem but above that I get Out of memory exception on the code line below. I have searched vastly of related issues, some stating about "using" key word and stream but since I am a beginner can someone please help me.

Image image = Bitmap.FromFile(Filename);

Here is my code

  private void LoadBtn_Click_1(object sender, EventArgs e)
    {
        OpenFileDialog newDialog = new OpenFileDialog();
        if (newDialog.ShowDialog() == DialogResult.OK)
        {
            images.Clear();

            string dirPath  = System.IO.Path.GetDirectoryName(newDialog.FileName.ToLower()); 
            DirectoryInfo di = new DirectoryInfo(dirPath);
            FileInfo[] finfos = di.GetFiles("*.*");

            foreach (FileInfo fi in finfos)
            {
                string ext = fi.Extension.ToLower();
                if ((ext.Equals(".png")) || (ext.Equals(".jpg")) || (ext.Equals(".tif")) ||                  (ext.Equals(".gif")))
                {
                    string Filename = fi.FullName;
                    Image image = Bitmap.FromFile(Filename); //exception occurs HERE
                    images.Add(image);
                    //this.imageList1.Images.Add(image);
                    //image.Dispose();
                }
            } 
        }

        pictureBox3.Image = images[0];

    }

I am using C#, windows forms. thanks

Answer 1

After taking a look at the software you mentioned, as I told you you don't need to load the whole image in memory if you only need a thumbnail.

So I'd create I class

class ImageAndThumb
{
    public Image Thumb;
    public Image Big;
    private string ImagePath;
    public ImageAndThumb(string fileName)
    {         
        ImagePath = fileName;
        Image image = Image.FromFile(fileName)
        Image thumb = img.GetThumbnailImage(200, 200, ()=>false, IntPtr.Zero);
    }
    public Image LoadBigImage()
    {
        Big = Image.FromFile(ImagePath);
        return Big;
    }
    public void UnloadImage()
    {
        Big = null;
    }

}

Now we use that class:

List<ImageAndThumb> Images = new List<ImageAndThumb>();
  private void LoadBtn_Click_1(object sender, EventArgs e)
    {
        OpenFileDialog newDialog = new OpenFileDialog();
        if (newDialog.ShowDialog() == DialogResult.OK)
        {
            Images.Clear();

            string dirPath  = System.IO.Path.GetDirectoryName(newDialog.FileName.ToLower()); 
            DirectoryInfo di = new DirectoryInfo(dirPath);
            FileInfo[] finfos = di.GetFiles("*.*");

            foreach (FileInfo fi in finfos)
            {
                string ext = fi.Extension.ToLower();
                if ((ext.Equals(".png")) || (ext.Equals(".jpg")) || (ext.Equals(".tif")) ||                  (ext.Equals(".gif")))
                {
                    string Filename = fi.FullName;
                    ImageAndThumb image = new ImageAndThumb(Filename); 
                    Images.Add(image);
                }
            } 
        }

        pictureBox3.Image = Images[0].Thumb; // << Much less memory usage;

    }

And now whenever you need to use an image load it first For example:

void ShowPicture(int index)
{
    Images[index].LoadBigImage();
    PictureBoxBig.image = Images[index].Big;
}
void ClosePicture(int index)
{
    Images[index].UnloadImage();
}

one good idea is to unload an image once you load another:

int currentPictureIndex = -1;
    void ShowPicture(int index)
    {
        Images[index].LoadBigImage();
        PictureBoxBig.image = Images[index].Big;
        if(CurrentPictureIndex > -1) ClosePicture(CurrentPictureIndex);
        currentPictureIndex = index;
    }