Add optional reference photo conditioning to Flux generation

server/utils/imageWorkflowV2.ts

@@ -1,5 +1,6 @@
 import editTemplate from '../assets/klein_v2_edit.json'
 import composeTemplate from '../assets/klein_v2_compose.json'
+import { addFluxGenerationReference } from './fluxReference'
 import refineTemplate from '../assets/klein_v2_refine.json'
 import generateTemplate from '../assets/klein_v2_generate.json'
 import kreaGenerateTemplate from '../assets/krea_v2_generate.json'
@@ -304,7 +305,7 @@ export function assertImageV2Graph(graph: WorkflowGraph, mode: ImageV2Mode, imag
   } else if (engine === 'krea') {
     assertKreaItiGraph(graph, mode)
   } else if (mode === 'generate') {
-    if (loaders.length) {
+    if (loaders.length && !(imageBName && loaders.length === 1 && graph['reference:load']?.inputs.image === imageBName)) {
       throw createError({
         statusCode: 500,
         statusMessage: 'Generate graph has a required LoadImage. Refusing to run an edit fallback.'
@@ -545,10 +546,11 @@ export function buildImageV2Workflow(params: ImageV2BuildParams) {
   if (!generate) applyScaleMegapixels(graph, params.megapixels)
 
   const userLoras = applyImageV2UserLoras(graph, imageV2UserStack(params, 'flux'), 'flux')
+  if (generate && params.imageBName) addFluxGenerationReference(graph, params.imageBName)
   const guider = Object.values(graph).find(node => node.class_type === 'CFGGuider' || node.class_type === 'BasicGuider')
   const modelFeed = Array.isArray(guider?.inputs.model) ? String(guider.inputs.model[0] || '') : ''
 
-  assertImageV2Graph(graph, params.mode, generate || refine ? undefined : params.imageBName, engine)
+  assertImageV2Graph(graph, params.mode, refine ? undefined : params.imageBName, engine)
 
   const loaders = loadImageNames(graph)
   console.log(JSON.stringify({