Image Processor Only Processing 1 Image - Then I Access Denied

I don't know what version of the script you have. I have in 1.1.0.6.

Check that your IsFolderWritable function code is like this.

// see if i can write to this folder by making a temp file then deleting it
// what I really need is a "readonly" on the Folder object but that only exists
// on the File object
function IsFolderWritable( inFolder ) {
    var isWritable = false;
    var f = File( inFolder + "deleteme.txt" );
    if ( f.open( "w", "TEXT", "????" ) ) {
        if ( f.write( "delete me" ) ) {
            if ( f.close() ) {
                if ( f.remove() ) {
                    isWritable = true;
                }
            }
        }
    }
    return isWritable;
}

If so, then make a backup copy of the original script. Then in the code, change the function code to this.

function IsFolderWritable( inFolder ) {
    var isWritable = false;
    var f = File( inFolder + "deleteme.txt" );
    if ( f.open( "w", "TEXT", "????" ) ) 
        {
        if ( f.write( "delete me" ) ) 
            {
            if ( f.close() ) 
                {
                if ( f.remove() ) {
                    isWritable = true;
                else 
                    alert(f.error + "\n\n" +f.fsName);
                }
            else 
                alert(f.error + "\n\n" +f.fsName);
            }
        else 
            alert(f.error + "\n\n" +f.fsName);
        }
    else 
        alert(f.error + "\n\n" +f.fsName);
    }
    return isWritable;
}

Run the script. Before the message about the impossibility of writing, you will get a message with the name of the file and an error. Perhaps this will help to understand the nature of the glitch.

If the glitch cannot be fixed based on the file error message, then replace the IsFolderWritable function code with this one.

function IsFolderWritable( inFolder ) { 
return true; 
}

This will eliminate the appearance of errors and messages in principle.

P.S. All this requires minimal knowledge of scripts and how functions are arranged in the code. Hope you figure it out.

It also happens on my C: drive, so it is not my external drive.