[RESOLVED] Images causing Out of Memory Condition

[AngelSpeaks]

Hi Everyone,

A little background. I have an application that creates picture communication boards. The boards may contain up to 40 images. The pictures and images that I include have all been resized, so the application has been running smoothly without running out of memory. Since I know most people don't have my photo editing skills, they will attempt to use their images. Also, this application will probably run on tablets which may not have the memory capacity.

I am checking for images that are more than 200KB in size and if so, extracting the thumbnails. I am disposing the images and running Garbage Collect, but I'm still having issues. My changes have allowed maybe 7 or 8 images to display before memory issues pop up plus the application is slower than a turtle.

Can the size, width, and height of the image be checked without loading it into memory?

Thanks for any help!!!!

Here is the code where the images are displayed (only code related to images are below):

                Call ResizeImage()

                         
                Image.FromFile(gstrPicture(intIndex)).Dispose()             'to free up memory

                GC.Collect()

              
                If _MyTemplateStatus = AppTemplateStatus.FontBorderChanged Then
                    
                    If File.Exists(gstrPicture(intIndex)) Then
                       Dim bnewBitMap As New Bitmap(bMyImage, newWidth, newHeight)
                        bMyImage.Dispose()
                        lblSymbols.Image = bnewBitMap
                        bnewBitMap = Nothing
  
                End If

                 'Dispose Images
                GC.Collect()

Here is the code to resize the image:

 Public Sub ResizeImage()
        'Get thumbnail if image is larger that 200k
        bMyImage = Nothing

        'Resize image
            Dim fileLengthb = New FileInfo(gstrPicture(intIndex)).Length
            If fileLengthb > gconMaxSize Then                      'size larger than 200kb
                bMyImage = Image.FromFile(gstrPicture(intIndex))
                intThumbWidth = bMyImage.Width / 10
                intThumbHeight = bMyImage.Height / 10
                bMyImage = bMyImage.GetThumbnailImage(intThumbHeight, intThumbWidth, Nothing, New IntPtr)
            Else
                bMyImage = Image.FromFile(gstrPicture(intIndex))
            End If

            sngWidth = bMyImage.Width
            sngHeight = bMyImage.Height
           
        sngHeightRatio = 1
        sngWidthRatio = 1

        If sngWidth > sngHeight Then
            sngHeightRatio = sngHeight / sngWidth
        End If
        If sngWidth < sngHeight Then
            sngWidthRatio = sngWidth / sngHeight
        End If
   
    End Sub

[passel]

I may be wrong, but this doesn't look right to me.

In the resize code you're setting bMyImage to Nothing without checking to see if it already had an image in it and disposing it.

This also looks pointless to me, but I could be wrong:

Image.FromFile(gstrPicture(intIndex)).Dispose() 'to free up memory

It looks like you're loading an image from a file and immediately disposing it. Why load it to begin with if you're going to immediately dispose it. That isn't freeing up any memory, it should just use some and immediately not use it, so you don't gain any memory, i.e. you don't waste any memory you just waste a bit of time.

Here you use bMyImage twice without disposing the first usage.
I guess you do that since you're using bMyImage on both sides of the assignment, but that seems like it would be a resource leak as well.

                bMyImage = Image.FromFile(gstrPicture(intIndex))
                intThumbWidth = bMyImage.Width / 10
                intThumbHeight = bMyImage.Height / 10
                bMyImage = bMyImage.GetThumbnailImage(intThumbHeight, intThumbWidth, Nothing, New IntPtr)

[si_the_geek]

Image.FromFile() loads a image file from disk, so this line doesn't make much sense:

                Image.FromFile(gstrPicture(intIndex)).Dispose()             'to free up memory

...this takes the time to load the file (again), and stores it in memory (again), just to the mark the memory that this new copy has used as no longer required.


The order of your first code snippet also seems a bit odd, but that may be just because of how you cut it down to post. This is how I think it should be:

                If _MyTemplateStatus = AppTemplateStatus.FontBorderChanged Then
                    
                    If File.Exists(gstrPicture(intIndex)) Then
                       Call ResizeImage()
                       Dim bnewBitMap As New Bitmap(bMyImage, newWidth, newHeight)
                       bMyImage.Dispose()
                       lblSymbols.Image = bnewBitMap
                       bnewBitMap = Nothing  
                       'Dispose Images
                       GC.Collect()
                End If

Also note that it would probably be better to convert ResizeImage to a function (which returns the value in bMyImage) and use a variable inside the first snippet to store it. Narrowing the scope of the variable will reduce the chances of memory issues.


edit: oops... it seems I took a while, passel got in a few minutes before me!

[AngelSpeaks]

I may be wrong, but this doesn't look right to me.

In the resize code you're setting bMyImage to Nothing without checking to see if it already had an image in it and disposing it.

This also looks pointless to me, but I could be wrong:

Image.FromFile(gstrPicture(intIndex)).Dispose() 'to free up memory

It looks like you're loading an image from a file and immediately disposing it. Why load it to begin with if you're going to immediately dispose it. That isn't freeing up any memory, it should just use some and immediately not use it, so you don't gain any memory, i.e. you don't waste any memory you just waste a bit of time.

Here you use bMyImage twice without disposing the first usage.
I guess you do that since you're using bMyImage on both sides of the assignment, but that seems like it would be a resource leak as well.

                bMyImage = Image.FromFile(gstrPicture(intIndex))
                intThumbWidth = bMyImage.Width / 10
                intThumbHeight = bMyImage.Height / 10
                bMyImage = bMyImage.GetThumbnailImage(intThumbHeight, intThumbWidth, Nothing, New IntPtr)

Thank you for your reply. I'm confused on this dispose. You (and si_the_geek also) commented on the Image.FromFile(gstrPicture(intIndex)).Dispose() not making any sense. This code is after calling ResizeImage. How should I be Disposing it?

[AngelSpeaks]

Image.FromFile() loads a image file from disk, so this line doesn't make much sense:

                Image.FromFile(gstrPicture(intIndex)).Dispose()             'to free up memory

...this takes the time to load the file (again), and stores it in memory (again), just to the mark the memory that this new copy has used as no longer required.


The order of your first code snippet also seems a bit odd, but that may be just because of how you cut it down to post. This is how I think it should be:

                If _MyTemplateStatus = AppTemplateStatus.FontBorderChanged Then
                    
                    If File.Exists(gstrPicture(intIndex)) Then
                       Call ResizeImage()
                       Dim bnewBitMap As New Bitmap(bMyImage, newWidth, newHeight)
                       bMyImage.Dispose()
                       lblSymbols.Image = bnewBitMap
                       bnewBitMap = Nothing  
                       'Dispose Images
                       GC.Collect()
                End If

Also note that it would probably be better to convert ResizeImage to a function (which returns the value in bMyImage) and use a variable inside the first snippet to store it. Narrowing the scope of the variable will reduce the chances of memory issues.


edit: oops... it seems I took a while, passel got in a few minutes before me!

Thanks for replying. There is a lot of code after the call to ResizeImage, but I could rework it. Thanks for the tips.

[passel]

Thank you for your reply. I'm confused on this dispose. You (and si_the_geek also) commented on the Image.FromFile(gstrPicture(intIndex)).Dispose() not making any sense. This code is after calling ResizeImage. How should I be Disposing it?

The image you loaded in the ResizeImage is referenced by bMyImage.
Once you're done with the loaded image, you would dispose of that, i.e. bMyImage.Dispose, which is what si_the_geek showed in his post.

But I believe this line:

bMyImage = bMyImage.GetThumbnailImage(intThumbHeight, intThumbWidth, Nothing, New IntPtr)

in the resize image method is flawed, because bMyImage is referenceing a bitmap and you clobber that reference with the return value of the GetThumbnailImage method call. You should be using a different variable on the left side of the = so that after you have the thumbnail, you can do a bMyImage.Dispose to get rid of the big bitmap. Of course, once you disposed of the big bitmap, you could then assign the local variable used on the left side of the = to bMyImage so bMyImage would reference the thumbnail.

Dim locBitmap as Bitmap = bMyImage.GetThumbnailImage(intThumbHeight, intThumbWidth, Nothing, New IntPtr)
bMyImage.Dispose
bMyImage = locBitmap

[AngelSpeaks]

Thanks again Passel. The line in question was copied from an example that I found. I thought it was a bit weird too.

Made the change you suggested, it's still on the slow side, but the whole communication board loaded. Thanks. I will continue to retweek using what you and si_the_geek suggest.

[boops boops]

You may gain some speed by commenting out the GC.Collects. If you get the disposing right, GC.Collect shouldn't be necessary. The effect of Collect is to force an immediate round of garbage collecting, with a processing overhead each time, instead of leaving it to the more efficient logic of the Garbage Collector. BB

[AngelSpeaks]

Thanks for the suggestion boops boops.

I did comment it out, but noticed no improvement. It was worth a try!

[AngelSpeaks]

Update, my out of memory condition seems to be resolved, the larger images are taking a long time to load. I am not surprised about this, I have a lot of very large images on my computer (I'm an amateur photographer) and even File Explorer takes a long time when I view my folders in large or medium icon view.

I did add a message box warning the user that they should consider resizing the images.

Thanks everyone for your help.