add discussion of samplers to VARIATIONS.md doc

Author: lstein

docs/features/VARIATIONS.md

@@ -123,3 +123,15 @@ two images. Here's the one I like best:
 As you can see, this is a very powerful tool, which when combined with subprompt
 weighting, gives you great control over the content and quality of your
 generated images.
+
+## Variations and Samplers
+
+The sampler you choose has a strong effect on variation strength. Some
+samplers, such as `k_euler_a` are very "creative" and produce significant
+amounts of image-to-image variation even when the seed is fixed and the
+`-v` argument is very low. Others are more deterministic. Feel free to
+experiment until you find the combination that you like.
+
+Also be aware of the [Perlin Noise](OTHER.md#thresholding-and-perlin-noise-initialization-options)
+feature, which provides another way of introducing variability into your
+image generation requests.