The file is busy. I can't delete it

I set copyright on the image. After that i need to delete the old file. But i can't because it's busy. I need rename the copyrighted file from "copyrighted_"+imageFile to imageFile.

public static void SetImageCopyright(string imageFile)
        {
            #region 
            //create a image object containing the photograph to watermark
            Image imgPhoto = Image.FromFile(imageFile);
            int phWidth = imgPhoto.Width;
            int phHeight = imgPhoto.Height;

            //create a Bitmap the Size of the original photograph
            Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);

            bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

            //load the Bitmap into a Graphics object 
            Graphics grPhoto = Graphics.FromImage(bmPhoto);


            //------------------------------------------------------------
            //Step #1 - Insert Copyright message
            //------------------------------------------------------------

            //Set the rendering quality for this Graphics object
            grPhoto.SmoothingMode = SmoothingMode.AntiAlias;

            //Draws the photo Image object at original size to the graphics object.
            grPhoto.DrawImage(
                imgPhoto,                               // Photo Image object
                new Rectangle(0, 0, phWidth, phHeight), // Rectangle structure
                0,                                      // x-coordinate of the portion of the source image to draw. 
                0,                                      // y-coordinate of the portion of the source image to draw. 
                phWidth,                                // Width of the portion of the source image to draw. 
                phHeight,                               // Height of the portion of the source image to draw. 
                GraphicsUnit.Pixel);                    // Units of measure 

            //-------------------------------------------------------
            //to maximize the size of the Copyright message we will 
            //test multiple Font sizes to determine the largest posible 
            //font we can use for the width of the Photograph
            //define an array of point sizes you would like to consider as possiblities
            //-------------------------------------------------------
            int[] sizes = new int[] { 25, 16, 12, 10, 8, 6, 4 };

            Font crFont = null;
            SizeF crSize = new SizeF();

            //Loop through the defined sizes checking the length of the Copyright string
            //If its length in pixles is less then the image width choose this Font size.
            for (int i = 0; i < 7; i++)
            {
                //set a Font object to Arial (i)pt, Bold
                crFont = new Font("arial", sizes[i], FontStyle.Bold);
                //Measure the Copyright string in this Font
                crSize = grPhoto.MeasureString("AlexMaslakov.ru", crFont);

                if ((ushort)crSize.Width < (ushort)phWidth)
                    break;
            }

            //Since all photographs will have varying heights, determine a 
            //position 5% from the bottom of the image
            int yPixlesFromBottom = (int)(phHeight * .05);

            //Now that we have a point size use the Copyrights string height 
            //to determine a y-coordinate to draw the string of the photograph
            float yPosFromBottom = ((phHeight - yPixlesFromBottom) - (crSize.Height / 2));

            //Determine its x-coordinate by calculating the center of the width of the image
            float xCenterOfImg = (phWidth / 2);

            //Define the text layout by setting the text alignment to centered
            StringFormat StrFormat = new StringFormat();
            StrFormat.Alignment = StringAlignment.Center;

            //define a Brush which is semi trasparent black (Alpha set to 153)
            SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));

            //Draw the Copyright string
            //grPhoto.DrawString(Copyright,                 //string of text
            //    crFont,                                   //font
            //    semiTransBrush2,                           //Brush
            //    new PointF(xCenterOfImg + 5, yPosFromBottom + 5),  //Position
            //    StrFormat);

            //define a Brush which is semi trasparent white (Alpha set to 153)
            SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));

            //Draw the Copyright string a second time to create a shadow effect
            //Make sure to move this text 1 pixel to the right and down 1 pixel
            grPhoto.DrawString("AlexMaslakov.ru",                 //string of text
                crFont,                                   //font
                semiTransBrush,                           //Brush
                new PointF(xCenterOfImg, yPosFromBottom),  //Position
                StrFormat);                               //Text alignment



            //------------------------------------------------------------
            //Step #2 - Insert Watermark image
            //------------------------------------------------------------

            //Create a Bitmap based on the previously modified photograph Bitmap
            Bitmap bmWatermark = new Bitmap(bmPhoto);
            bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
            //Load this Bitmap into a new Graphic Object
            Graphics grWatermark = Graphics.FromImage(bmWatermark);

            //To achieve a transulcent watermark we will apply (2) color 
            //manipulations by defineing a ImageAttributes object and 
            //seting (2) of its properties.
            ImageAttributes imageAttributes = new ImageAttributes();

            //The first step in manipulating the watermark image is to replace 
            //the background color with one that is trasparent (Alpha=0, R=0, G=0, B=0)
            //to do this we will use a Colormap and use this to define a RemapTable
            ColorMap colorMap = new ColorMap();

            //My watermark was defined with a background of 100% Green this will
            //be the color we search for and replace with transparency
            colorMap.OldColor = Color.FromArgb(255, 0, 255开发者_JS百科, 0);
            colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);

            ColorMap[] remapTable = { colorMap };

            imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

            //The second color manipulation is used to change the opacity of the 
            //watermark.  This is done by applying a 5x5 matrix that contains the 
            //coordinates for the RGBA space.  By setting the 3rd row and 3rd column 
            //to 0.3f we achive a level of opacity
            float[][] colorMatrixElements = { 
                                                new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},       
                                                new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},        
                                                new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},        
                                                new float[] {0.0f,  0.0f,  0.0f,  0.3f, 0.0f},        
                                                new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}};
            ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default,
                ColorAdjustType.Bitmap);
            #endregion

            //Replace the original photgraphs bitmap with the new Bitmap
            imgPhoto = bmWatermark;
            grPhoto.Dispose();
            grWatermark.Dispose();
            bmPhoto.Dispose();

            //save new image to file system.
             imgPhoto.Save("copyrighted_"+imageFile, ImageFormat.Jpeg);
            imgPhoto.Dispose();

        }

When you use Image.FromFile, the file is open as long as the image object exists. You have to dispose the image before you can replace the file.

The image that you loaded is never disposed in the code, you just replace the reference to it with the watermarked image. Dispose the image before discarding the reference to it:

//Replace the original photgraphs bitmap with the new Bitmap
imgPhoto.Dispose();
imgPhoto = bmWatermark;

Now you can save the image replacing the original file.

You open the file imgPhoto and try to Save it, while it is still open (it isn't disposed). What you could do is open the file to a MemoryStream and create an Image from the stream. After that, you can save it to the original file by overwriting it.

// Open the file here
Image original = Image.FromFile(file);

// Create a MemoryStream in which to save the image
MemoryStream originalStream = new MemoryStream();

// Save the Image to the MemoryStream
original.Save(originalStream, original.RawFormat);

// Dispose the original image, so you can overwrite it later
original.Dispose();

Now you can use the Image.FromStream method to create an Image which you can manipulate.

I'm no C# expert but it looks like you're not disposing the original image since near the end you just reassign the variable: imgPhoto = bmWatermark;

Try using a new variable rather than resusing imgPhoto and dispose of both at the end before deleting.

Files can't be "busy", but "locked".

Make sure no other application holds your file open, and make sure that you Dispose all file handles to that file, before attempting to do further things with that file.

If you can't find who has locked your file, you could try "process explorer".