library(shiny)
library(ggplot2)

p <- ggplot2::qplot(1, 1)

server <- function(input, output, session) {
  output$a <- output$b <- output$c <- renderPlot(p)
}

# ui's are wrapped by div
ui <- fluidPage(
  plotOutput("a", width = 200, height = 200) %>% tags$div(style = "display: inline-block"),
  plotOutput("b", width = 200, height = 200) %>% tags$div(style = "display: inline-block"),
  plotOutput("c", width = 200, height = 200) %>% tags$div(style = "display: inline-block")
)

# ui's does not have to be wrapped by div anymore
ui_new <- fluidPage(
  plotOutput("a", width = 200, height = 200, style = "display: inline-block"),
  plotOutput("b", width = 200, height = 200, style = "display: inline-block"),
  plotOutput("c", width = 200, height = 200, style = "display: inline-block")
)

# compare
runGadget(ui, server)
runGadget(ui_new, server)