diff --git a/denops/traqvim/main.ts b/denops/traqvim/main.ts
index 1997cb8..73a3100 100644
--- a/denops/traqvim/main.ts
+++ b/denops/traqvim/main.ts
@@ -45,11 +45,26 @@ export async function main(denops: Denops) {
   // oauthの仮オブジェクト
   let oauth: OAuth;
   denops.dispatcher = {
-    async getFile(fileId: unknown): Promise<unknown> {
+    async getFile(
+      fileId: unknown,
+      opts?: unknown,
+    ): Promise<unknown> {
       assert(fileId, is.String);
+      assert(
+        opts,
+        is.OptionalOf(is.ObjectOf({
+          maxWidth: is.Number,
+          maxHeight: is.Number,
+        })),
+      );
       const file: Uint8Array = await downloadFile(fileId);
       // denops-sixel-view.vimのsixel_viewがUint8Arrayを受け取れる必要がある
-      const sixel = await denops.dispatch("sixel_view", "img2sixel", file);
+      const sixel = await denops.dispatch(
+        "sixel_view",
+        "img2sixel",
+        file,
+        opts,
+      );
       assert(
         sixel,
         is.ObjectOf({
diff --git a/doc/traqvim.jax b/doc/traqvim.jax
index 73bb4b1..ce3a13e 100644
--- a/doc/traqvim.jax
+++ b/doc/traqvim.jax
@@ -280,8 +280,18 @@ https://github.com/gw31415/denops-sixel-view.vim
 	endfunction
 
 	function s:preview_img(fileId) abort
+		let font_height = 12
+		let font_width = font_height / 2
+		let retina_scale = 2
 		" download the file and convert it to sixel data
-		let sixel = denops#request("traqvim", "getFile", [a:fileId])
+		let sixel = denops#request("traqvim", "getFile",
+					\[
+					\	a:fileId,
+					\	#{
+					\		maxWidth: winwidth('.') * font_width / 2 * retina_scale,
+					\		maxHeight: winheight('.') * font_height / 2 * retina_scale,
+					\	}
+					\])
 		call sixel_view#view_sixel(sixel['data'], 0, 0)
 	endfunction