How to Download and Display an Image from an Url in R

how to download and display an image from an URL in R?

If I try your code it looks like the image is downloaded. However, when opened with windows image viewer it also says it is corrupt.
The reason for this is that you don't have specified the mode in the download.file statement.

Try this:

download.file(y,'y.jpg', mode = 'wb')

For more info about the mode is see ?download.file

This way at least the file that you downloaded is working.

To view the image in R, have a look at

jj <- readJPEG("y.jpg",native=TRUE)
plot(0:1,0:1,type="n",ann=FALSE,axes=FALSE)
rasterImage(jj,0,0,1,1)

or how to read.jpeg in R 2.15
or Displaying images in R in version 3.1.0

How to directly read an image file from a url address in R

Just save the image as a temporary file:

myurl <- "http://upload.wikimedia.org/wikipedia/commons/9/95/Apollonian_spheres.jpg"
z <- tempfile()
download.file(myurl,z,mode="wb")
pic <- readJPEG(z)
file.remove(z) # cleanup

R: Download image using rvest

Here's one example to download the R logo into the current directory.

library(rvest)
url <- "https://www.r-project.org"
imgsrc <- read_html(url) %>%
  html_node(xpath = '//*/img') %>%
  html_attr('src')
imgsrc
# [1] "/Rlogo.png"

# side-effect!
download.file(paste0(url, imgsrc), destfile = basename(imgsrc))

EDIT

Since authentication is involved, Austin's suggestion of using a session is certainly required. Try this:

library(rvest)
library(httr)
sess <- html_session(url)
imgsrc <- sess %>%
  read_html() %>%
  html_node(xpath = '//*/img') %>%
  html_attr('src')
img <- jump_to(sess, paste0(url, imgsrc))

# side-effect!
writeBin(img$response$content, basename(imgsrc))

Load image from website

Here is an approach that worked for me for a single image (it could be wrapped in a function to be used in the loop):

con <- url("http://actor.epa.gov/actor/image?format=png%3Aw1000%2Ch1000&casrn=1478-61-1",
    open='rb')

rawpng <- readBin(con, what='raw', n=50000)

close(con)

png1 <- readPNG(rawpng)

I tested it using:

plot(1:10, type='n')
rasterImage( as.raster(png1), 3,3,8,8 )

It took some guesswork to get the 50000 and that may be different for other files (actually I should have used 48849, but then it really would be likely to change between files).

Why can't I view or open downloaded PNG file from URL

Loos like you have to set mode = "wb" in download.file. The manual says:

The choice of binary transfer (‘mode = "wb"’ or ‘"ab"’) is important on Windows, since unlike Unix-alikes it does distinguish between text and binary files and for text transfers changes ‘\n’ line endings to ‘\r\n’ (aka ‘CRLF’).

On Windows, if ‘mode’ is not supplied (‘missing()’) and ‘url’ ends in one of ‘.gz’, ‘.bz2’, ‘.xz’, ‘.tgz’, ‘.zip’, ‘.jar’, ‘.rda’, ‘.rds’ or ‘.RData’, ‘mode = "wb"’ is set so that a binary transfer is done to help unwary users.

So for the single file try:

download.file("http://assets.pokemon.com/assets/cms2/img/pokedex/full/001.png", 
              destfile=file.path("C:/Users/vsvas/Desktop/test","first_img.png"),
              mode = "wb")

Display images from web in shiny R

Be careful when sharing your code as you just shared your private API key. I suggest you generate a new one.

It does not work because shiny only serves files that are in the ~/www directory. So they should be downloaded to that folder for your method to work.

Perhaps an easier way to go about this is simply to embed the image. Looking at the code it looks like json$url is the URL to the image.

library(shiny)

ui <- fluidPage(
  h4("Embedded image"),
  uiOutput("img")
)

server <- function(input, output, session) {
  output$img <- renderUI({
      tags$img(src = "https://www.r-project.org/logo/Rlogo.png")
  })
}

shinyApp(ui, server)

You could try the above without hardcoding https://www.r-project.org/logo/Rlogo.png and using your json$url instead.

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