Add a text to a PNG file

#if 0
png_text text_ptr[1];
text_ptr[0].key = "userInfo";
char png_userInfo[100];
sprintf(png_userInfo, "%d", m_userInfo);
text_ptr[0].text = png_userInfo;
text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
png_set_text(png_ptr, info_ptr, text_ptr, 1);
#endif