Memory Consumed but not released

I have an application that will provided end users to upload multiple folders with large amounts of images. I have noticed that using the ActiveX control in both XP and Vista in IE7/IE8 that when the initial image load happend memory allocated for IE increased greatly and then incrementally with each upload. Once the upload is complete none of the memory allocated to IE is released. Subsequent upload will consume more memory until control throws an error or simply locks up. Is this a known issue and is there a remedy?

We are using the 6.0.16 version.

Here are the relevant settings:
//Configure upload settings.
iu.addParam("AllowFolderUpload", "true");
iu.addParam("IncludeSubfolders", "true");
iu.addParam("ShowSubfolders", "true");

iu.addParam("FilesPerOnePackageCount", "1");
iu.addParam("AutoRecoverMaxTriesCount", "2");
iu.addParam("AutoRecoverTimeOut", "10000");
iu.addParam("MaxConnectionCount", "1");
iu.addParam("TimeOut", "0");

iu.addParam("AllowAutoRotate", "true");
iu.addParam("AllowLargePreview", "true");

iu.addParam("FileMask", "*.jpeg;*.jpg;*.png;*.gif;*.bmp");

//Set image size restrictions.
iu.addParam("MinImageWidth", "250");
iu.addParam("MinImageHeight", "250");
iu.addParam("MaxFileCount", "0");
iu.addParam("MaxFileSize", "0");
iu.addParam("MaxTotalFileSize", "0");

//Exclude the source file from upload because only
//resized versions of the photo will be sent.
iu.addParam("UploadSourceFile", "false");

//Configure settings of the optimized image. Optimized image
//is resized to 1200x1200 with JPEG quality = 60 and EXIF
//metadata is preserved.
iu.addParam("UploadThumbnail1FitMode", "Fit");
iu.addParam("UploadThumbnail1Width", "2500");
iu.addParam("UploadThumbnail1Height", "2500");
iu.addParam("UploadThumbnail1JpegQuality", "80");
iu.addParam("UploadThumbnail1CopyExif", "true");

We have been uploading large amount of images, mostly jpeg, but also have bmp, png as well. Seeing that we are only using the scaled down version of the thumb, we should only receive jpg on the backend.

Here is one test sample: 500 folders / 5 images per folder (2mb/ folder, 1GB total )

Virtual Memory Usage: 588MB at start of upload
729MB after adding 500 folders to upload queue
729MB-839MB gradual increase while uploading
839MB Test Complete

Memory Usage (iexplore.exe): 79MB at start of upload
295MB Test Complete

Similar results have been repeated on multiple test workstations.