Determine filenames of thumbnail files

presentation.Export(filename, "PNG", sizeX, sizeY);

Creates thumbnail images of all slides in the PowerPoint presentation. 

My problem is that the thumbnail filenames change according to the Language of PowerPoint.

On an English PowerPoint, the thumbnail files are: "slide1.png", "slide2.png", etc.

On Hebrew PowerPoint: שקופית1.png,  שקופית2.png, etc.

Is there a programming (e.g. VBA) way to know the thumbnail filenames beforehand?

Thanks,

Arie