diff --git a/spec/executionContextSpec.ts b/spec/executionContextSpec.ts
index dfa0096..e6744f2 100644
--- a/spec/executionContextSpec.ts
+++ b/spec/executionContextSpec.ts
@@ -83,8 +83,7 @@ export default describe('executionContext', () => {
   it('should addBuiltInImages()', async done => {
     let all = await context.getAllFiles()
     expect(all.find(i => i.name === 'rose:')).toBeUndefined()
-    const builtIn = await context.addBuiltInImages()
-    expect(builtIn.find(i => i.name === 'rose:')).toBeDefined()
+    await context.addBuiltInImages()
     all = await context.getAllFiles()
     expect(all.find(i => i.name === 'rose:')).toBeDefined()
     done()
diff --git a/spec/imageHomeSpec.ts b/spec/imageHomeSpec.ts
index a367ca5..fa93920 100644
--- a/spec/imageHomeSpec.ts
+++ b/spec/imageHomeSpec.ts
@@ -20,4 +20,18 @@ export default describe('imageHome', () => {
     expect(all.find(f => f.name === 'holocaust.jpg')).toBeTruthy()
     done()
   })
+
+  it('should addBuiltInImages()', async done => {
+
+    const imageHome = createImageHome()
+    let all = await imageHome.getAll()
+    expect(all.find(i => i.name === 'rose:')).toBeUndefined()
+    // const builtIn = await context.addBuiltInImages()
+    // expect(builtIn.find(i => i.name === 'rose:')).toBeDefined()
+    await imageHome.addBuiltInImages()
+    all = await imageHome.getAll()// .getAllFiles()
+    expect(all.find(i => i.name === 'rose:')).toBeDefined()
+    done()
+  })
+
 })
diff --git a/src/executionContext.ts b/src/executionContext.ts
index a3f7d81..174fbd2 100644
--- a/src/executionContext.ts
+++ b/src/executionContext.ts
@@ -1,22 +1,23 @@
-import { ImageHome, ExecuteConfig, ExecuteResult, execute, ExecuteCommand, createImageHome, MagickInputFile, MagickFile, extractInfo } from '.'
-import pMap from 'p-map'
-import { asOutputFile, asInputFile, getBuiltInImages } from './util'
+import { createImageHome, execute, ExecuteCommand, ExecuteConfig, ExecuteResult, ImageHome, MagickFile, MagickInputFile } from '.'
+import { getBuiltInImages } from './util'
 
 /**
- * Allow multiple execute() calls remembering previus execute() generated output files and previous given input files that can be used as input files in next calls.
+ * Allow multiple execute() calls remembering previus execute() generated output files and previous given input files that
+ * can be used as input files in next calls.
  */
 export interface ExecutionContext {
   execute(configOrCommands: ExecuteConfig|ExecuteCommand|string): Promise<ExecuteResult>
+  /** programmatically add new files so they are available if following execute() calls */
   addFiles(files: MagickFile[]): void
+  /** get all the files currently available in this context */
   getAllFiles(): Promise<MagickInputFile[]>
-  addBuiltInImages(): Promise<MagickFile[]>
+  // /** add built-in images like `rose:` to this execution context so they are present in getAllFiles() */
+  addBuiltInImages(): Promise<void>
   getFile(name: string): Promise<MagickInputFile>
 }
 
 class ExecutionContextImpl implements ExecutionContext {
 
-  private builtInImages: MagickInputFile[] = []
-
   constructor(private imageHome: ImageHome = createImageHome()) {
   }
 
@@ -39,26 +40,14 @@ class ExecutionContextImpl implements ExecutionContext {
 
   async getAllFiles(): Promise<MagickInputFile[]> {
     const all = await this.imageHome.getAll()
-    return all.concat(this.builtInImages)
+    return all// .concat(this.builtInImages)
   }
 
   async getFile(name: string): Promise<MagickInputFile> {
-    return (await this.imageHome.get(name)) || this.builtInImages.find(i => i.name === name)
+    return (await this.imageHome.get(name))// || this.builtInImages.find(i => i.name === name)
   }
-
   async addBuiltInImages() {
-    if (!this.builtInImages.length) {
-      this.builtInImages = await getBuiltInImages()
-  //     const builtInImages = ['rose:', 'logo:', 'wizard:', 'granite:', 'netscape:']
-  //     this.builtInImages = await pMap(builtInImages, async name=>{
-  //       const info = await extractInfo(name)
-  //       // const outputName = `output1.${info[0].image.format.toLowerCase()}`
-  //       const {outputFiles} = await execute({commands:`convert ${name} ${`output1.${info[0].image.format.toLowerCase()}`}`} )
-  //       outputFiles[0].name = name
-  //       return await asInputFile(outputFiles[0])
-  //     })
-    }
-    return this.builtInImages
+    return this.imageHome.addBuiltInImages()
   }
 
   static create(inheritFrom?: ExecutionContext) {
diff --git a/src/imageHome.ts b/src/imageHome.ts
index a557cfe..74bc036 100644
--- a/src/imageHome.ts
+++ b/src/imageHome.ts
@@ -1,11 +1,12 @@
-import { MagickInputFile, MagickFile } from '.'
-import { asInputFile } from './util/file'
+import { MagickInputFile, MagickFile, asInputFile, getBuiltInImages } from '.'
+import pMap from 'p-map'
 
 export interface ImageHome {
   get(name: string): Promise<MagickInputFile>
   register(file: MagickFile, name?: string): void
   isRegistered(name: string): boolean
   getAll(): Promise<MagickInputFile[]>
+  addBuiltInImages(): Promise<void>
 }
 
 type MagickInputFilePromise = Promise<MagickInputFile> & { resolved: true }
@@ -13,6 +14,7 @@ type MagickInputFilePromise = Promise<MagickInputFile> & { resolved: true }
 class ImageHomeImpl implements ImageHome {
 
   private images: { [name: string]: MagickInputFilePromise } = {}
+  private builtInImagesAdded: boolean = false
 
   get(name: string): Promise<MagickInputFile> {
     return this.images[name]
@@ -34,5 +36,13 @@ class ImageHomeImpl implements ImageHome {
   isRegistered(name: string, andReady: boolean= true): boolean {
     return this.images[name] && (andReady && this.images[name].resolved)
   }
+
+  async addBuiltInImages() {
+    if (!this.builtInImagesAdded) {
+      await pMap(await getBuiltInImages(), img => this.register(img))
+      this.builtInImagesAdded = true
+    }
+  }
+
 }
 export function createImageHome() {return new ImageHomeImpl()}