diff --git a/api/token.go b/api/token.go
index a8ac8d7..266f430 100644
--- a/api/token.go
+++ b/api/token.go
@@ -7,6 +7,8 @@ import (
 	"net/http"
 	"path/filepath"
 
+	"os"
+
 	"github.com/gin-gonic/gin"
 	"github.com/gotify/location"
 	"github.com/gotify/server/auth"
@@ -80,6 +82,9 @@ func (a *TokenAPI) DeleteApplication(ctx *gin.Context) {
 	withID(ctx, "id", func(id uint) {
 		if app := a.DB.GetApplicationByID(id); app != nil && app.UserID == auth.GetUserID(ctx) {
 			a.DB.DeleteApplicationByID(id)
+			if app.Image != "" {
+				os.Remove(a.ImageDir + app.Image)
+			}
 		} else {
 			ctx.AbortWithError(404, fmt.Errorf("app with id %d doesn't exists", id))
 		}
@@ -117,14 +122,23 @@ func (a *TokenAPI) UploadApplicationImage(ctx *gin.Context) {
 				return
 			}
 
-			name := auth.GenerateImageName()
 			ext := filepath.Ext(file.Filename)
+
+			name := auth.GenerateImageName()
+			for exist(a.ImageDir + name + ext) {
+				name = auth.GenerateImageName()
+			}
+
 			err = ctx.SaveUploadedFile(file, a.ImageDir+name+ext)
 			if err != nil {
 				ctx.AbortWithError(500, err)
 				return
 			}
 
+			if app.Image != "" {
+				os.Remove(a.ImageDir + app.Image)
+			}
+
 			app.Image = name + ext
 			a.DB.UpdateApplication(app)
 			ctx.JSON(200, withAbsoluteURL(ctx, app))
@@ -134,6 +148,13 @@ func (a *TokenAPI) UploadApplicationImage(ctx *gin.Context) {
 	})
 }
 
+func exist(path string) bool {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return false
+	}
+	return true
+}
+
 func withAbsoluteURL(ctx *gin.Context, app *model.Application) *model.Application {
 	url := location.Get(ctx)
 
diff --git a/api/token_test.go b/api/token_test.go
index 243017a..77cdef3 100644
--- a/api/token_test.go
+++ b/api/token_test.go
@@ -15,6 +15,8 @@ import (
 	"os"
 	"reflect"
 
+	"io/ioutil"
+
 	"github.com/bouk/monkey"
 	"github.com/gin-gonic/gin"
 	"github.com/gotify/server/mode"
@@ -359,7 +361,56 @@ func (s *TokenSuite) Test_UploadAppImage_WithImageFile_expectSuccess() {
 	assert.Equal(s.T(), 200, s.recorder.Code)
 	_, err = os.Stat("PorrUa5b1IIK3yKo_Pp6ww_9v.png")
 	assert.Nil(s.T(), err)
-	assert.Nil(s.T(), os.Remove("PorrUa5b1IIK3yKo_Pp6ww_9v.png"))
+
+	s.a.DeleteApplication(s.ctx)
+
+	_, err = os.Stat("PorrUa5b1IIK3yKo_Pp6ww_9v.png")
+	assert.True(s.T(), os.IsNotExist(err))
+}
+
+func (s *TokenSuite) Test_UploadAppImage_WithImageFile_DeleteExstingImageAndGenerateNewName() {
+	s.db.User(5)
+	s.db.CreateApplication(&model.Application{UserID: 5, ID: 1, Image: "PorrUa5b1IIK3yKo_Pp6ww_9v.png"})
+
+	cType, buffer, err := upload(map[string]*os.File{"file": mustOpen("../test/assets/image.png")})
+	assert.Nil(s.T(), err)
+	s.ctx.Request = httptest.NewRequest("POST", "/irrelevant", &buffer)
+	s.ctx.Request.Header.Set("Content-Type", cType)
+	test.WithUser(s.ctx, 5)
+	s.ctx.Params = gin.Params{{Key: "id", Value: "1"}}
+	fakeImage(s.T(), "PorrUa5b1IIK3yKo_Pp6ww_9v.png")
+
+	s.a.UploadApplicationImage(s.ctx)
+
+	assert.Equal(s.T(), 200, s.recorder.Code)
+
+	_, err = os.Stat("PorrUa5b1IIK3yKo_Pp6ww_9v.png")
+	assert.True(s.T(), os.IsNotExist(err))
+	_, err = os.Stat("Zal6-ySIuL-T3EMLCcFtityHn.png")
+	assert.Nil(s.T(), err)
+	assert.Nil(s.T(), os.Remove("Zal6-ySIuL-T3EMLCcFtityHn.png"))
+}
+
+func (s *TokenSuite) Test_UploadAppImage_WithImageFile_DeleteExistingImage() {
+	s.db.User(5)
+	s.db.CreateApplication(&model.Application{UserID: 5, ID: 1, Image: "existing.png"})
+
+	fakeImage(s.T(), "existing.png")
+	cType, buffer, err := upload(map[string]*os.File{"file": mustOpen("../test/assets/image.png")})
+	assert.Nil(s.T(), err)
+	s.ctx.Request = httptest.NewRequest("POST", "/irrelevant", &buffer)
+	s.ctx.Request.Header.Set("Content-Type", cType)
+	test.WithUser(s.ctx, 5)
+	s.ctx.Params = gin.Params{{Key: "id", Value: "1"}}
+
+	s.a.UploadApplicationImage(s.ctx)
+
+	assert.Equal(s.T(), 200, s.recorder.Code)
+
+	_, err = os.Stat("existing.png")
+	assert.True(s.T(), os.IsNotExist(err))
+
+	os.Remove("PorrUa5b1IIK3yKo_Pp6ww_9v.png")
 }
 
 func (s *TokenSuite) Test_UploadAppImage_WithTextFile_expectBadRequest() {
@@ -444,3 +495,11 @@ func mustOpen(f string) *os.File {
 	}
 	return r
 }
+
+func fakeImage(t *testing.T, path string) {
+	data, err := ioutil.ReadFile("../test/assets/image.png")
+	assert.Nil(t, err)
+	// Write data to dst
+	err = ioutil.WriteFile(path, data, 0644)
+	assert.Nil(t, err)
+}