Iam hereby making a feature request where you can set the icon emblem size in the Thunar preferences window. Iam using Fluxbox and have no GTK configuration tools to set my look & feel preferences, which leads into that my embelms fallback to their largest size.
Created attachment 840 Zoomed emblem When zooming in icon mode, the emblem also gets zoomed in, overlapping the picture...
Created attachment 841 Possible patch The problem is that the icon theme you are using (Tango) provides larger emblems only as scalable vector graphics, which means there's no precise size for emblems for icons at sizes larger than 48x48. The attached patch limits emblem sizes to 36x36px, which should fix your problem.
Committed with revision 23612. 2006-11-03 Benedikt Meurer <benny@xfce.org> * thunar/thunar-icon-renderer.c(thunar_icon_renderer_render): Make sure emblems don't get too large with SVG icon themes. Bug #2466.