Include an example of adding an image

docs/src/examples.md

@@ -326,4 +326,33 @@ XLSX.setBorder(s, "F112,F113"; allsides = ["style" => "thin", "color" => "black"
 XLSX.setBorder(s, "B112:B114,D112:D115"; outside = ["style" => "thin", "color" => "black"])
 
 XLSX.writexlsx("myNewTemplate.xlsx", f, overwrite=true)
-```
+```
+
+## Adding a plot image
+
+Use Julia functionality to create a chart based upon data from a spreadsheet and then add that chart 
+(as a static image) back into the worksheet.
+
+![image|320x500](./images/Add_image_1.png)
+
+```julia
+using CairoMakie, XLSX
+
+f=opentemplate("Example_add_chart.xlsx")
+table = XLSX.gettable(f[1])
+x = 1:length(table.data[1])
+
+fig = Figure()
+ax = Axis(fig[1, 1], xticks=(x, table.data[1]))
+barplot!(ax, x, table.data[2])
+
+# Write PNG to IOBuffer
+io = IOBuffer()
+show(io, MIME("image/png"), fig)
+
+XLSX.addImage(f[1], "D2:H12", io)
+
+XLSX.writexlsx("Example_add_chart_out.xlsx", f, overwrite=true)
+```
+
+![image|320x500](./images/Add_image_2.png)

src/images.jl

@@ -109,9 +109,8 @@ Supported formats (auto-detected): PNG, JPEG, GIF.
 
 # Keyword Arguments
 
-- `size`: provide the desired size of the image as a tuple of integers: `(width_px, height_px)`. Actual size 
-will snap to the nearest actual cell boundaries. If `nothing` (default), the image's native pixel size is used. 
-Ignored if `ref` is a cell range.
+- `size`: provide the desired size of the image as a tuple of integers: `(width_px, height_px)`. If `nothing` (default), 
+the image's native pixel size is used. Ignored if `ref` is a cell range. Actual size will snap to the nearest cell boundaries.
 
 # Return Value
 

src/table.jl

@@ -916,6 +916,7 @@ XLSXFile("blank.xlsx") containing 1 Worksheet
 
 """
 function XLSXFile(table)
+    Tables.istable(table) || throw(XLSXError("Input must be a Tables.jl compatible table."))
     isempty(Tables.rows(table)) && throw(XLSXError("Cannot create XLSXFile from an empty table."))
     xf = newxlsx()
     writetable!(xf[1], table)