added spec_image, spec_hist, spec_boxplot and fixed some cran comments
diff --git a/man/spec_hist.Rd b/man/spec_hist.Rd
new file mode 100644
index 0000000..9deb046
--- /dev/null
+++ b/man/spec_hist.Rd
@@ -0,0 +1,119 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/mini_plots.R
+\name{spec_hist}
+\alias{spec_hist}
+\alias{spec_boxplot}
+\title{Helper functions to generate inline sparklines}
+\usage{
+spec_hist(
+  x,
+  width = 200,
+  height = 50,
+  res = 300,
+  breaks = "Sturges",
+  same_lim = TRUE,
+  lim = NULL,
+  xaxt = "n",
+  yaxt = "n",
+  ann = FALSE,
+  col = "lightgray",
+  border = NULL,
+  dir = if (is_latex()) rmd_files_dir() else tempdir(),
+  file = NULL,
+  file_type = if (is_latex()) "png" else "svg",
+  ...
+)
+
+spec_boxplot(
+  x,
+  width = 200,
+  height = 50,
+  res = 300,
+  add_label = FALSE,
+  label_digits = 2,
+  same_lim = TRUE,
+  lim = NULL,
+  xaxt = "n",
+  yaxt = "n",
+  ann = FALSE,
+  col = "lightgray",
+  border = NULL,
+  boxlty = 0,
+  medcol = "red",
+  medlwd = 1,
+  dir = if (is_latex()) rmd_files_dir() else tempdir(),
+  file = NULL,
+  file_type = if (is_latex()) "png" else "svg",
+  ...
+)
+}
+\arguments{
+\item{x}{Vector of values or List of vectors of values.}
+
+\item{width}{The width of the plot in pixel}
+
+\item{height}{The height of the plot in pixel}
+
+\item{res}{The resolution of the plot. Default is 300.}
+
+\item{breaks}{one of:
+    \itemize{
+      \item a vector giving the breakpoints between histogram cells,
+      \item a function to compute the vector of breakpoints,
+      \item a single number giving the number of cells for the histogram,
+      \item a character string naming an algorithm to compute the
+      number of cells (see \sQuote{Details}),
+      \item a function to compute the number of cells.
+    }
+    In the last three cases the number is a suggestion only; as the
+    breakpoints will be set to \code{\link{pretty}} values, the number
+    is limited to \code{1e6} (with a warning if it was larger).  If
+    \code{breaks} is a function, the \code{x} vector is supplied to it
+    as the only argument (and the number of breaks is only limited by
+    the amount of available memory).
+  }
+
+\item{same_lim}{T/F. If x is a list of vectors, should all the plots be
+plotted in the same range? Default is True.}
+
+\item{lim}{Manually specify plotting range in the form of \code{c(0, 10)}.}
+
+\item{xaxt}{On/Off for xaxis text}
+
+\item{yaxt}{On/Off for yaxis text}
+
+\item{ann}{On/Off for annotations (titles and axis titles)}
+
+\item{col}{Color for the fill of the histogram bar/boxplot box.}
+
+\item{border}{Color for the border.}
+
+\item{dir}{Directory of where the images will be saved.}
+
+\item{file}{File name. If not provided, a random name will be used}
+
+\item{file_type}{Graphic device. Support \code{png} or \code{svg}. SVG is recommended
+for HTML output}
+
+\item{...}{further arguments and \link[graphics]{graphical parameters} passed to
+    \code{\link[graphics]{plot.histogram}} and thence to \code{\link[graphics]{title}} and
+    \code{\link[graphics]{axis}} (if \code{plot = TRUE}).}
+
+\item{add_label}{For boxplot. T/F to add labels for min, mean and max.}
+
+\item{label_digits}{If T for add_label, rounding digits for the label.
+Default is 2.}
+
+\item{boxlty}{Boxplot - box boarder type}
+
+\item{medcol}{Boxplot - median line color}
+
+\item{medlwd}{Boxplot - median line width}
+}
+\description{
+These functions helps you quickly generate sets of sparkline
+style plots using base R plotting system. Currently, we support histogram
+and boxplot. You can use them together with \code{column_spec} to
+generate inline plot in tables. By default, this function will save images
+in a folder called "kableExtra" and return the address of the file.
+}