adding troubleshooting notes for black image

README.md

@@ -81,5 +81,10 @@ Update the file ```appConfig.json``` to add more models. Some models need you to
 ## Result is a black image
 Some parameters lead to black images, deactivate them, one by one, and re-run the whole process:
 - safety checker
-- attention slicing
-- a or the wrong auto encoder
+- a or the wrong auto encoder
+- the wrong schedulder/solver (e.g. DPMMultiStep seems to be incompatible with SD15, better use DDPMScheduler)
+
+Also I faced a couple of bugs when using the attention_slicing method (see https://discuss.huggingface.co/t/activating-attention-slicing-leads-to-black-images-when-running-diffusion-more-than-once/68623):
+
+- you cannot re-run the inferencing process when using attention_slicing
+- don't pass cross_attention_kwargs or guidance_scale to the pipeline