Randomly show an image for shiny app

[Normal_distribution]

I have a number of photos that I have put in my www folder. Is there a way to make my shiny app randomly pick and show one of them everytime the app is launched?

[ismirsehregal]

Sure, please check the following example app:

library(shiny)

# Create dummy images -----------------------------------------------------
img_names = paste0("img", 1:10, ".jpg")

if(!dir.exists("www")){
  dir.create("www")
}

for(i in seq_along(img_names)){
  png(file = paste0("www/", img_names[i]), bg = colors()[i])
  par(mar = c(0,0,0,0))
  plot(c(0, 1), c(0, 1), ann = F, bty = 'n', type = 'n', xaxt = 'n', yaxt = 'n')
  text(x = 0.5, y = 0.5, img_names[i], 
       cex = 1.6, col = "black")
  dev.off()
}

# Actual app --------------------------------------------------------------
ui <- fluidPage(
  titlePanel("Random Image"),
  mainPanel(
    fluidRow(
      htmlOutput("random_image_out")
    )
  )
)

server = function(input, output, session){
  # pretending we don't know about img_names
  www_imgs <- list.files(path = "www", pattern = "*.jpg$")
  
  # random_image for each new shiny-session
  random_image <- www_imgs[round(runif(1, min = 1, max = length(www_imgs)), digits = 0)]
  
  output$random_image_out = renderUI({
    tags$img(src=random_image, width="50%", height="50%")
  })
}

shinyApp(ui, server)

[Normal_distribution]

This works great! Thank you!