diff --git a/functionality/filesharing/filesharing_functionality.go b/functionality/filesharing/filesharing_functionality.go
index 0b8510f..b3436f4 100644
--- a/functionality/filesharing/filesharing_functionality.go
+++ b/functionality/filesharing/filesharing_functionality.go
@@ -17,6 +17,7 @@ import (
 
 	"cwtch.im/cwtch/model"
 	"cwtch.im/cwtch/model/attr"
+	"cwtch.im/cwtch/model/constants"
 	"cwtch.im/cwtch/peer"
 	"cwtch.im/cwtch/protocol/files"
 	"git.openprivacy.ca/openprivacy/log"
@@ -29,14 +30,14 @@ type Functionality struct {
 // FunctionalityGate returns filesharing if enabled in the given experiment map
 // Note: Experiment maps are currently in libcwtch-go
 func FunctionalityGate(experimentMap map[string]bool) (*Functionality, error) {
-	if experimentMap["filesharing"] {
+	if experimentMap[constants.FileSharingExperiment] {
 		return new(Functionality), nil
 	}
 	return nil, errors.New("filesharing is not enabled")
 }
 
 func PreviewFunctionalityGate(experimentMap map[string]bool) (*Functionality, error) {
-	if experimentMap["filesharing"] == true && experimentMap["filesharing-images"] == true {
+	if experimentMap[constants.FileSharingExperiment] == true && experimentMap[constants.ImagePreviewsExperiment] == true {
 		return new(Functionality), nil
 	}
 	return nil, errors.New("image previews are not enabled")
@@ -57,8 +58,16 @@ func (om *OverlayMessage) FileKey() string {
 
 // checks file size and file name. *DOES NOT* check user settings or contact state
 func (om *OverlayMessage) ShouldAutoDL() bool {
+	if om.Size > constants.ImagePreviewMaxSizeInBytes {
+		return false
+	}
 	lname := strings.ToLower(om.Name)
-	return om.Size <= 20971520 && (strings.HasSuffix(lname, "jpg") || strings.HasSuffix(lname, "jpeg") || strings.HasSuffix(lname, "png") || strings.HasSuffix(lname, "gif") || strings.HasSuffix(lname, "webp") || strings.HasSuffix(lname, "bmp"))
+	for _, s := range constants.AUTODL_FILE_EXTS {
+		if strings.HasSuffix(lname, s) {
+			return true
+		}
+	}
+	return false
 }
 
 // DownloadFile given a profile, a conversation handle and a file sharing key, start off a download process
diff --git a/model/constants/experiments.go b/model/constants/experiments.go
new file mode 100644
index 0000000..9adb50e
--- /dev/null
+++ b/model/constants/experiments.go
@@ -0,0 +1,14 @@
+package constants
+
+// Allows file sharing
+const FileSharingExperiment = "filesharing"
+
+// Causes images (up to ImagePreviewMaxSizeInBytes, from accepted contacts) to auto-dl and preview
+// requires FileSharingExperiment to be enabled
+const ImagePreviewsExperiment = "filesharing-images"
+
+// Files up to this size will be autodownloaded using ImagePreviewsExperiment
+const ImagePreviewMaxSizeInBytes = 20971520
+
+// Files with these extensions will be autodownloaded using ImagePreviewsExperiment
+var AUTODL_FILE_EXTS = [...]string{".jpg", ".jpeg", ".png", ".gif", ".webp", ".bmp"}
diff --git a/testing/filesharing/file_sharing_integration_test.go b/testing/filesharing/file_sharing_integration_test.go
index 5c1bd13..47a604f 100644
--- a/testing/filesharing/file_sharing_integration_test.go
+++ b/testing/filesharing/file_sharing_integration_test.go
@@ -2,6 +2,11 @@ package filesharing
 
 import (
 	"crypto/rand"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+
 	app2 "cwtch.im/cwtch/app"
 	"cwtch.im/cwtch/app/utils"
 	"cwtch.im/cwtch/event"
@@ -12,14 +17,10 @@ import (
 	"cwtch.im/cwtch/peer"
 	"cwtch.im/cwtch/protocol/connections"
 	"cwtch.im/cwtch/protocol/files"
-	"encoding/base64"
-	"encoding/hex"
-	"encoding/json"
-	"fmt"
 	"git.openprivacy.ca/openprivacy/connectivity/tor"
 	"git.openprivacy.ca/openprivacy/log"
+
 	// Import SQL Cipher
-	_ "github.com/mutecomm/go-sqlcipher/v4"
 	mrand "math/rand"
 	"os"
 	"os/user"
@@ -28,6 +29,8 @@ import (
 	"runtime/pprof"
 	"testing"
 	"time"
+
+	_ "github.com/mutecomm/go-sqlcipher/v4"
 )
 
 func waitForPeerPeerConnection(t *testing.T, peera peer.CwtchPeer, peerb peer.CwtchPeer) {
@@ -121,7 +124,7 @@ func TestFileSharing(t *testing.T) {
 
 	fmt.Println("Alice and Bob are Connected!!")
 
-	filesharingFunctionality, _ := filesharing.FunctionalityGate(map[string]bool{"filesharing": true})
+	filesharingFunctionality, _ := filesharing.FunctionalityGate(map[string]bool{constants.FileSharingExperiment: true})
 
 	err = filesharingFunctionality.ShareFile("cwtch.png", alice, 1)