Update PROMPT-GUIDE.md

PROMPT-GUIDE.md

@@ -11,7 +11,10 @@
     * Prefix `species` category with `species:`, e.g.  `species:leopard`
     * Same for `species`, `character`, `copyright`, `lore`, and `artist`
     * Depending on your tool, you may need to prefix colon as `\:`, e.g. `meta\:portrait`
-* Stable Diffusion 2.x does not do well if you are trying to replicate a style of a specific artist; use the prompt to describe your goal instead
+* Stable Diffusion 2.x does not do well if you are trying to replicate a style of a specific artist; use the prompt to describe your goal instead of the art style
+    *  This is a known issue with 2.x
+    *  See example prompts to understand what is and is not possible
+    *  Consider using `img2img` with 1.x models if specific artist styles are important to you
 * Recommended tags:
     * `anthro`
     * `species:X`