Can't pass the directory to addResourcePath

[nfuryn]

ui <- fluidPage(
  shinyDirButton("directory", "Folder select", "Please select a folder")
)

server <- function(input, output, session) {
  library(shinyFiles)
  volumes <- c(Home = fs::path_home(), "R Installation" = R.home(), getVolumes()())
  shinyDirChoose(input, "directory", roots = volumes, session = session, restrictions = system.file(package = "base"), allowDirCreate = FALSE)
  dirname <- reactive({parseDirPath(volumes, input$directory)})
  observe({
    cat("\ninput$directory value:\n\n")
    print(input$directory)
  })
  output$directorypath <- renderPrint({
    if (is.integer(input$directory)) {
      cat("No directory has been selected (shinyDirChoose)")
    } else {
      parseDirPath(volumes, input$directory)
    }
  })
  dirpath <- ""
  
  observe({
    if(!is.null(dirname)){
      print(dirname())
      dirpath <- renderText(dirname())
    }
  })
  
  if (!is.null(dirpath) && dirpath != '') {
    addResourcePath("photos", dirpath)
  }
}

When in the app, the updated ResourcePath should allow me to show a local photo, but it doesn't. It shows a broken image. Here's the relevant part of the code:

observeEvent(input$addButton, {
    filtered_data <- filtered_data %>%
      filter(Photos == input$tag)
    if (nrow(filtered_data) > 0) {
      leafletProxy("map") %>%
        clearMarkers() %>%
        addMarkers(
          lng = filtered_data$GPSLongitude,
          lat = filtered_data$GPSLatitude,
          popup = paste0("<img src='photos/", filtered_data$filepath, "' width='300px' height='300px'>")})
        )
  })

However, if I use this in the code and manually enter my path, then it works:
addResourcePath("photos", (mypath))

[vnijs]

Can you use addResourcePath dynamically? I.e., add it while the app is already running?