Show image size on view page (#25884)

This simply shows the Image size on the view page. This is useful, if
you search a image with a specific size.


![grafik](https://github.com/go-gitea/gitea/assets/15185051/9868e361-1c2e-447f-b824-70aa28bafcbc)

routers/web/repo/view.go

@@ -9,6 +9,7 @@ import (
 	gocontext "context"
 	"encoding/base64"
 	"fmt"
+	"image"
 	"io"
 	"net/http"
 	"net/url"
@@ -16,6 +17,10 @@ import (
 	"strings"
 	"time"
 
+	_ "image/gif"  // for processing gif images
+	_ "image/jpeg" // for processing jpeg images
+	_ "image/png"  // for processing png images
+
 	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"  // for processing bmp images
+	_ "golang.org/x/image/webp" // for processing webp images
 )
 
 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%dpx", img.Width, img.Height)
+		}
+	}
+
 	if ctx.Repo.CanEnableEditor(ctx, 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">
+			{{.ImageSize}}
+		</div>
+	{{end}}
 </div>