diff --git a/hugolib/integrationtest_builder.go b/hugolib/integrationtest_builder.go
index e5c9a6856..58e751892 100644
--- a/hugolib/integrationtest_builder.go
+++ b/hugolib/integrationtest_builder.go
@@ -2,6 +2,7 @@ package hugolib
 
 import (
 	"bytes"
+	"encoding/base64"
 	"fmt"
 	"io"
 	"os"
@@ -40,12 +41,13 @@ func NewIntegrationTestBuilder(conf IntegrationTestConfig) *IntegrationTestBuild
 	}
 
 	if conf.NeedsOsFS {
-		doClean := true
 		tempDir, clean, err := htesting.CreateTempDir(hugofs.Os, "hugo-integration-test")
 		c.Assert(err, qt.IsNil)
 		conf.WorkingDir = filepath.Join(tempDir, conf.WorkingDir)
-		if doClean {
+		if !conf.PrintAndKeepTempDir {
 			c.Cleanup(clean)
+		} else {
+			fmt.Println("\nUsing WorkingDir dir:", conf.WorkingDir)
 		}
 	} else if conf.WorkingDir == "" {
 		conf.WorkingDir = helpers.FilePathSeparator
@@ -278,10 +280,19 @@ func (s *IntegrationTestBuilder) initBuilder() {
 
 		logger := loggers.NewBasicLoggerForWriter(s.Cfg.LogLevel, &s.logBuff)
 
+		isBinaryRe := regexp.MustCompile(`^(.*)(\.png|\.jpg)$`)
+
 		for _, f := range s.data.Files {
 			filename := filepath.Join(s.Cfg.WorkingDir, f.Name)
+			data := bytes.TrimSuffix(f.Data, []byte("\n"))
+			if isBinaryRe.MatchString(filename) {
+				var err error
+				data, err = base64.StdEncoding.DecodeString(string(data))
+				s.Assert(err, qt.IsNil)
+
+			}
 			s.Assert(afs.MkdirAll(filepath.Dir(filename), 0777), qt.IsNil)
-			s.Assert(afero.WriteFile(afs, filename, bytes.TrimSuffix(f.Data, []byte("\n")), 0666), qt.IsNil)
+			s.Assert(afero.WriteFile(afs, filename, data, 0666), qt.IsNil)
 		}
 
 		cfg, _, err := LoadConfig(
@@ -297,6 +308,8 @@ func (s *IntegrationTestBuilder) initBuilder() {
 			},
 		)
 
+		s.Assert(err, qt.IsNil)
+
 		cfg.Set("workingDir", s.Cfg.WorkingDir)
 
 		fs := hugofs.NewFrom(afs, cfg)
@@ -457,6 +470,9 @@ type IntegrationTestConfig struct {
 	// Whether it needs the real file system (e.g. for js.Build tests).
 	NeedsOsFS bool
 
+	// Do not remove the temp dir after the test.
+	PrintAndKeepTempDir bool
+
 	// Whether to run npm install before Build.
 	NeedsNpmInstall bool
 
diff --git a/resources/image_cache.go b/resources/image_cache.go
index b5832f740..ca651fd5c 100644
--- a/resources/image_cache.go
+++ b/resources/image_cache.go
@@ -95,6 +95,7 @@ func (c *imageCache) getOrCreate(
 		rp := img.getResourcePaths()
 		rp.relTargetDirFile.file = relTarget.file
 		img.setSourceFilename(info.Name)
+		img.setMediaType(conf.TargetFormat.MediaType())
 
 		if err := img.InitConfig(r); err != nil {
 			return err
diff --git a/resources/integration_test.go b/resources/integration_test.go
new file mode 100644
index 000000000..19cf8c198
--- /dev/null
+++ b/resources/integration_test.go
@@ -0,0 +1,69 @@
+// Copyright 2022 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resources_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/gohugoio/hugo/hugolib"
+)
+
+// Issue 8931
+func TestImageCache(t *testing.T) {
+
+	files := `
+-- config.toml --
+baseURL = "https://example.org"
+-- content/mybundle/index.md --
+---
+title: "My Bundle"
+---
+-- content/mybundle/pixel.png --
+iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
+-- layouts/foo.html --
+-- layouts/index.html --
+{{ $p := site.GetPage "mybundle"}}
+{{ $img := $p.Resources.Get "pixel.png" }}
+{{ $gif := $img.Resize "1x1 gif" }}
+{{ $bmp := $img.Resize "1x1 bmp" }}
+
+gif: {{ $gif.RelPermalink }}|{{ $gif.MediaType }}|
+bmp: {{ $bmp.RelPermalink }}|{{ $bmp.MediaType }}|	
+`
+
+	b := hugolib.NewIntegrationTestBuilder(
+		hugolib.IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+			NeedsOsFS:   true,
+			Running:     true,
+		}).Build()
+
+	assertImages := func() {
+		b.AssertFileContent("public/index.html", `
+		gif: /mybundle/pixel_hu8aa3346827e49d756ff4e630147c42b5_70_1x1_resize_box_3.gif|image/gif|
+		bmp: /mybundle/pixel_hu8aa3346827e49d756ff4e630147c42b5_70_1x1_resize_box_3.bmp|image/bmp|
+		
+		`)
+	}
+
+	assertImages()
+
+	b.EditFileReplace("content/mybundle/index.md", func(s string) string { return strings.ReplaceAll(s, "Bundle", "BUNDLE") })
+	b.Build()
+
+	assertImages()
+
+}