Can not reduce size of the docker image after deleting the build tools from child image that were installed in base image

Hi,

I am using docker-alpine 3.3 as the base image and building another image from it. Following is the dockerfile for this

FROM xxx/alpine3.3:latest
MAINTAINER xxx@xxx.com
RUN apk update
RUN apk add --update bash
RUN apk add --update nodejs
RUN apk add --update curl
RUN npm install -g gulp-cli
RUN apk add --update python

RUN apk add --update make
RUN apk add --update g++

Then this created docker images is used as the base image for another docker file where I do npm install and then remove the build tools like python, make and g++ after npm install. Following is the docker file
FROM dockerbase:latest
MAINTAINER xxx@xxx.com
COPY common /opt/project1324/common
RUN /usr/bin/npm install
RUN apk del python
RUN apk del make
RUN apk del g++

But the size of the docker image has no difference for the cases when I delete those packages and do not delete those packages. Infact, the size is a little bit more when I delete those packages.

Is there a way to delete those build tools from all the layers of docker image so that the size of the docker image decreases.

How can I remove these build tools?