diff --git a/bot.go b/bot.go
index c6ca084..1cef4d4 100644
--- a/bot.go
+++ b/bot.go
@@ -208,30 +208,33 @@ func (bot *BotAPI) UploadFile(endpoint string, params Params, fieldname string,
 
 	ms.SetupRequest(req)
 
-	res, err := bot.Client.Do(req)
+	resp, err := bot.Client.Do(req)
 	if err != nil {
 		return APIResponse{}, err
 	}
-	defer res.Body.Close()
+	defer resp.Body.Close()
 
-	bytes, err := ioutil.ReadAll(res.Body)
+	var apiResp APIResponse
+	bytes, err := bot.decodeAPIResponse(resp.Body, &apiResp)
 	if err != nil {
-		return APIResponse{}, err
+		return apiResp, err
 	}
 
 	if bot.Debug {
 		log.Printf("Endpoint: %s, response: %s\n", endpoint, string(bytes))
 	}
 
-	var apiResp APIResponse
+	if !apiResp.Ok {
+		var parameters ResponseParameters
 
-	err = json.Unmarshal(bytes, &apiResp)
-	if err != nil {
-		return APIResponse{}, err
-	}
+		if apiResp.Parameters != nil {
+			parameters = *apiResp.Parameters
+		}
 
-	if !apiResp.Ok {
-		return APIResponse{}, errors.New(apiResp.Description)
+		return apiResp, Error{
+			Message:            apiResp.Description,
+			ResponseParameters: parameters,
+		}
 	}
 
 	return apiResp, nil
diff --git a/configs.go b/configs.go
index 0258d74..6ff2867 100644
--- a/configs.go
+++ b/configs.go
@@ -1363,7 +1363,9 @@ func (config UploadStickerConfig) getFile() interface{} {
 }
 
 func (config UploadStickerConfig) useExistingFile() bool {
-	return false
+	_, ok := config.PNGSticker.(string)
+
+	return ok
 }
 
 // NewStickerSetConfig allows creating a new sticker set.
@@ -1453,7 +1455,9 @@ func (config AddStickerConfig) getFile() interface{} {
 }
 
 func (config AddStickerConfig) useExistingFile() bool {
-	return false
+	_, ok := config.PNGSticker.(string)
+
+	return ok
 }
 
 // SetStickerPositionConfig allows you to change the position of a sticker in a set.