Texture memory decisions start with what the camera can resolve. A close foreground surface may need substantial image detail, while the same source image on a distant object contributes only a few pixels. Review the most demanding view before reducing every texture by the same amount.
Save a working copy and keep original images intact. Make reduced variants in a separate folder with recognizable names. This lets you restore one important texture without reconstructing the entire material.
Count pixels before judging file size
A compressed image's size on disk does not directly describe its decoded memory use. Dimensions, channel count and internal precision matter. Additional copies, mip levels and rendering-system overhead can add further costs. Use the image file size as a storage measurement, not a complete memory estimate.
For a simple arithmetic example, a 4096 by 4096 image contains four times as many pixels as a 2048 by 2048 image. If a representation used four 32-bit channels, the larger image's pixel values alone would occupy 256 MiB. Treat that figure as a planning estimate. Measure your scene to find its actual Blender and render-device allocation.
Collect dimensions and usage for the largest images first. A list of a dozen large textures is easier to act on than an undifferentiated count of every file in the project folder.
Assign detail to the shot's visible surfaces
Inspect the nearest camera view of each major asset. Estimate how much of the frame its textured region occupies and look at whether the image is stretched, tiled or only partly used by its UVs. A large source image with most pixels outside the useful UV area can still provide little visible detail.
Compare a reduced image with the original at final output size. Look for changes in recognizable marks, edge definition and material response. Zooming far beyond the delivery size can make a harmless reduction appear unacceptable, while checking only a small viewport can hide a lost foreground feature.
For animation, use the closest approach and any focus change. A texture that works in the opening wide shot may become inadequate when the camera reaches the object. Evaluate the whole planned range before deleting a higher-resolution working variant.
Look for duplicate image data
Inspect whether several materials can use the same image data block. Repeated imports can produce separately named images that point to identical source content. Names alone are insufficient: compare paths, dimensions and the images themselves before consolidating them.
Two textures with similar names may contain different edits or channel packing. Repoint one material at a time and render a comparison. Keep the intended color-space interpretation and node connections; reusing an image incorrectly can change a roughness or normal response even when the filename looks right.
The missing-texture workflow explains how to inspect image paths. That inspection also helps identify copies loaded from temporary extraction folders and versions that should remain distinct.
Reduce technical maps with their purpose in mind
Base color, roughness and normal images do different jobs, so they do not always need identical dimensions. Test each map's contribution before making a reduction. A low-contrast roughness map may survive a change that removes an important small feature from a normal map.
Watch for thin masks and cutout foliage. Downsampling an alpha image can change the coverage of small leaves and stems, affecting both the outline and shadows. Compare the silhouette against a contrasting background as well as the material's close appearance.
Keep data maps in the appropriate non-color interpretation. The color-management guide distinguishes texture color from control data. A memory reduction should not also introduce an accidental color-space conversion that changes the material.
Measure in a repeatable scene state
Open the same saved scene and use the same render engine, device and camera for each comparison. Record the memory information your Blender version and system tools expose, noting whether a number describes system memory, device memory or a peak during rendering. Those measurements are not interchangeable.
Change one group of images, then rerender the same view. Record both the visual result and the measurement. Texture reductions may leave geometry, volume or acceleration-structure memory unchanged, so a small total reduction does not prove the image changes failed.
If the renderer runs out of memory, isolate a smaller scene section to investigate. The vegetation optimization guide addresses other scene costs that can accompany repeated textured objects. Avoid assigning every memory problem to the largest image without checking the rest of the scene.
Keep the accepted texture set reproducible
Save the revised material references and reopen the project. Confirm that reduced variants load from the intended folder and that no important image was left pointing at a temporary export. Keep a short note identifying the camera range used for approval. A later close-up is a reason to revisit that budget and restore selected detail.