Show image size on view page

options/locale/locale_en-US.ini

@@ -1164,6 +1164,7 @@ audio_not_supported_in_browser = Your browser does not support the HTML5 'audio'
 stored_lfs = Stored with Git LFS
 symbolic_link = Symbolic link
 executable_file = Executable File
+image_size = Size: %s
 commit_graph = Commit Graph
 commit_graph.select = Select branches
 commit_graph.hide_pr_refs = Hide Pull Requests

routers/web/repo/view.go

@@ -9,13 +9,18 @@ import (
 	gocontext "context"
 	"encoding/base64"
 	"fmt"
+	"image"
 	"io"
 	"net/http"
 	"net/url"
 	"path"
 	"strings"
 	"time"
 
+	_ "image/gif"
+	_ "image/jpeg"
+	_ "image/png"
+
 	activities_model "code.gitea.io/gitea/models/activities"
 	admin_model "code.gitea.io/gitea/models/admin"
 	asymkey_model "code.gitea.io/gitea/models/asymkey"
@@ -44,6 +49,9 @@ import (
 	issue_service "code.gitea.io/gitea/services/issue"
 
 	"github.com/nektos/act/pkg/model"
+
+	_ "golang.org/x/image/bmp"
+	_ "golang.org/x/image/webp"
 )
 
 const (
@@ -578,6 +586,15 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 		}
 	}
 
+	if fInfo.st.IsImage() && !fInfo.st.IsSvgImage() {
+		img, _, err := image.DecodeConfig(bytes.NewReader(buf))
+		if err == nil {
+			// There are Image formats go can't decode
+			// Instead of throwing an error in that case, we show the size only when we can decode
+			ctx.Data["ImageSize"] = fmt.Sprintf("%dx%d", img.Width, img.Height)
+		}
+	}
+
 	if ctx.Repo.CanEnableEditor(ctx.Doer) {
 		if lfsLock != nil && lfsLock.OwnerID != ctx.Doer.ID {
 			ctx.Data["CanDeleteFile"] = false

templates/repo/file_info.tmpl

@@ -30,4 +30,9 @@
 			{{.locale.Tr "repo.executable_file"}}
 		</div>
 	{{end}}
+	{{if .ImageSize}}
+		<div class="file-info-entry">
+			{{.locale.Tr "repo.image_size" .ImageSize}}
+		</div>
+	{{end}}
 </div>