Changing an image with user input, shiny, renderImage - r

Question

I have an app that shows data as well as a picture based on user input. I have the following code in my ui:
selectInput("var",
label = "Choose a penguin to display",
choices = c("Bowie", "Cookie",
"Mango", "Renesme"),
selected = "Bowie"),
dateRangeInput("dates",
"Date range",
start = "2017-06-16",
end = as.character(Sys.Date())),
imageOutput("img1")
),
mainPanel(plotOutput("plot")
)
)
))
And the following in my server:
output$plot <- renderPlot({
penguin <- switch(input$var,
"Bowie" = filter(date_swim, penguin == 'Bowie'),
"Cookie" = filter(date_swim, penguin == 'Cookie'),
"Mango" = filter(date_swim, penguin == 'Mango'),
"Renesme" = filter(date_swim, penguin == 'Renesme'))
getSwim(min = input$dates[1],
max = input$dates[2],
p = penguin)
})
output$img1 <- renderImage({ #This is where the image is set
if(input$var == "Bowie"){
img(src = "Bowie.png", height = 240, width = 300)
}
else if(input$var == "Cookie"){
img(src = "Cookie.png", height = 240, width = 300)
}
else if(input$var == "Renesme"){
img(src = "Renesme.png", height = 240, width = 300)
}
else if(input$var == "Mango"){
img(src = "Mango.png", height = 240, width = 300)
}
})
})
When I run, where the image should be I see the error message:
character argument vector expected.

Answer 1

I think this is a bit misleading in the docs but for RenderImage() you want to use list() function and not img(). I reworked your server.R file a bit:
download.file("http://dehayf5mhw1h7.cloudfront.net/wp-content/uploads/sites/38/2016/01/18220900/Getty_011816_Bluepenguin.jpg",
destfile = "Bowie.png")
download.file("http://3.bp.blogspot.com/_cBH6cWZr1IU/TUURNp7LADI/AAAAAAAABsY/76UhGhmxjzY/s640/penguin+cookies_0018.jpg",
destfile = "Cookie.png")
function(input, output) {
output$img1 <- renderImage({ #This is where the image is set
if(input$var == "Bowie"){
list(src = "Bowie.png", height = 240, width = 300)
}
else if(input$var == "Cookie"){
list(src = "Cookie.png", height = 240, width = 300)
}
else if(input$var == "Renesme"){
list(src = "Renesme.png", height = 240, width = 300)
}
else if(input$var == "Mango"){
list(src = "Mango.png", height = 240, width = 300)
}
})