Unable to Load png file from SD card to image button esp32S3

I am using lvgl version 8.3.6 and am trying to load a png image from SD card to set as image button src. In my lv_conf file i have the following settings,

#define LV_USE_LOG 1
#define LV_LOG_LEVEL LV_LOG_LEVEL_INFO
#define LV_LOG_PRINTF 1
#define LV_USE_PNG 1
#define LV_USE_FS_STDIO 1
#if LV_USE_FS_STDIO
#define LV_FS_STDIO_LETTER ‘A’
#define LV_FS_STDIO_PATH “”
#define LV_FS_STDIO_CACHE_SIZE 0
#endif

I have copied the image in the SD card in root folder by name of “SealCheckIcon75.png” . it 's a 75x75 pixel image
In my arduino code when i call the following code
in set up i have:
lv_init();
lv_png_init();
_lv_fs_init();

and then in a a function i call the following code

lv_imgbtn_set_src(ui_ImgButton1, LV_IMGBTN_STATE_PRESSED, NULL, “A:/SealCheckIcon75.png”, NULL);

i get an error as follows:
lv_fs_open: Can’t open file (A:/SealCheckIcon75.png): unknown driver letter (in lv_fs.c line #68)

i have even tried,
lv_imgbtn_set_src(ui_ImgButton1, LV_IMGBTN_STATE_PRESSED, NULL, “A:SealCheckIcon75.png”, NULL);

lv_imgbtn_set_src(ui_ImgButton1, LV_IMGBTN_STATE_PRESSED, NULL, “/SealCheckIcon75.png”, NULL);

I am not able to make out where the issue is. Can someone please help me out. i have been stuck on this for quite some time now.

This is currently an LVGL related question, please ask at LVGL forum, you’ll get more help there: https://forum.lvgl.io/