Your stick boots on small laptops and big monitors alike, and one wallpaper cannot suit both. Carry one theme per resolution and let resolution_fit choose automatically - here is the setup and its one strict naming rule.
One wallpaper cannot look right on every screen. A theme designed at 1920x1080 turns tiny or stretched on a 1024x768 laptop and soft on a 4K monitor - and a technician's stick boots on all of them. Ventoy's answer is to carry several themes, one per resolution, and let the resolution_fit option pick the matching one at every boot. Here is the exact setup, including the naming rule everything depends on.
Create a folder per resolution you meet in the field - 1024x768, 1600x900 and 1920x1080 cover most machines. Each folder holds a complete small theme: a theme.txt and a wallpaper exported at exactly that resolution. Keep the design identical across the set (same colours, same logo placement) so the menu feels like one product at every size. Do not just resize one image and call it done - adjust the menu box in each theme.txt so text stays readable at the small size.
This is the part everyone misses. With resolution_fit on, Ventoy filters themes by checking whether the theme file's full path contains the resolution string, like 1600x900 - with a lowercase x. The string can live in a folder name (theme_1600x900) or in the file name (theme_1600x900.txt). A folder named Theme_1600X900 with a capital X does not match. Name every folder with the exact pattern from the start and the filter works first time.
file becomes a list of theme paths instead of one pathdefault_file must be 0 - with any other value, resolution_fit does nothing (0 normally means random choice; with the filter on, the random choice happens only among matching themes)resolution_fit is set to 1 (it exists in Ventoy 1.0.86 and later)gfxmode set to "max" lets each machine boot at its best resolution, so the matching theme is the right oneIf exactly one theme matches the booted resolution, it is used every time - which is the normal, predictable case.
Automatic selection is the default story, not a lock-in. Press F5 and open Tools - Resolution Configuration to change the current resolution - with resolution_fit on, Ventoy immediately swaps to the theme matching the new resolution. Tools - Theme Select lets you preview any installed theme for that session; the choice is temporary and the next boot goes back to the automatic rule. Use these menus while designing the set, then let the filter run the show in the field.
The video covers one theme end to end - this guide multiplies it per resolution.
Watch Full VideoVentoy filters the list down to themes whose path contains the current resolution string. If your set has no match for an unusual resolution, keep one broadly usable theme in the list and test your set on the oldest machine you support - in practice the common resolutions (1024x768, 1600x900, 1920x1080) cover nearly every PC.
Check the three conditions together: file must be a list of more than one theme, default_file must be 0, and resolution_fit must be 1 - and Ventoy must be 1.0.86 or later. Also check the path naming: the resolution string uses a lowercase x, like 1600x900.
Yes. Set default_file to the position of that theme in the file list (1 for the first, 2 for the second) - but note resolution_fit then switches off, because it only works when default_file is 0. It is a choice: one fixed theme, or automatic per-resolution selection.