tryCatch [WARNING] Could not fetch resource anovaformulario.png

General
1

Warnings like

[WARNING] Could not fetch resource anovaformulario.png

seems not be catched by tryCatch like in code bellow using rmarkdown::render

tryCatch(
  {
    rmarkdown::render("filename.Rmd", output_format = "html_document", quiet = TRUE)
  },
  
  warning = function(cond) {
    
    if (grepl("fetch resource",cond$message)) {
      cat("Missing image file\n")
    } 
    
  }
)