# UPDATETHUMBNAIL System Variable [GstarCAD 2026](Help%20System/GSTARCAD/2026/Index.md) → [System Variables](Help%20System/GSTARCAD/2026/System%20Variables/(System%20Variables).md) → [U](Help%20System/GSTARCAD/2026/System%20Variables/U/(U).md) ## Function Description: The UPDATETHUMBNAIL system variable is used to control the update of thumbnail preview for views and layouts. | | | | --- | --- | | Type | Bitcode | | Saved in | Drawing | | Initial value | 15 | | Range | 0 ~ 16 | ## System Variable Value: **0:** do not update preview **1:** update preview of views in model space **2:** update preview of views in layout **4:** update preview of layout **8:** update preview when created, modified, or restored layout or views **16:**update preview when saving a drawing --- [Original help](https://www.gstarcad.net/help/GstarCAD_2026_en-US/detail/systemVariables/UPDATETHUMBNAIL.html) · © Gstarsoft Co., Ltd.