We can flexibly add a local image (i.e., an image residing on disk) inside of a table with local_image() function. The function provides a convenient way to generate an HTML fragment using an on-disk PNG or SVG. Because this function is currently HTML-based, it is only useful for HTML table output. To use this function inside of data cells, it is recommended that the text_transform() function is used. With that function, we can specify which data cells to target and then include a local_image() call within the required user-defined function (for the fn argument). If we want to include an image in other places (e.g., in the header, within footnote text, etc.) we need to use local_image() within the html() helper function.

## Usage

local_image(filename, height = 30)

## Arguments

filename

A path to an image file.

height

The absolute height (px) of the image in the table cell.

## Value

A character object with an HTML fragment that can be placed inside of a cell.

## Details

By itself, the function creates an HTML image tag with an image URI embedded within. We can easily experiment with a local PNG or SVG image that's available in the gt package using the test_image() function. Using that, the call local_image(file = test_image(type = "png")) evaluates to:

<img src=<data URI> style=\"height:30px;\">

where a height of 30px is a default height chosen to work well within the heights of most table rows.

## Examples

Create a tibble that contains heights of an image in pixels (one column as a string, the other as numerical values), then, create a gt table. Use the text_transform() function to insert a local test image (PNG) image with the various sizes.

dplyr::tibble(
pixels = px(seq(10, 35, 5)),
image = seq(10, 35, 5)
) %>%
gt() %>%
text_transform(
locations = cells_body(columns = image),
fn = function(x) {
local_image(
filename = test_image(type = "png"),
height = as.numeric(x)
)
}
)

## Function ID

8-2

Other image addition functions: ggplot_image(), test_image(), web_image()